Reproductive Aggregations Research Articles

Do risk-prone behaviours compromise reproduction and increase vulnerability of fish aggregations exposed to fishing?

Human disturbances can prompt natural anti-predator behaviours in animals, affecting how energy is traded off between immediate survival and reproduction. In our study of male squaretail groupers (Plectropomus areolatus) in India's Lakshadweep archipelago, we investigated the impact of fishing pressure on anti-predatory responses and reproductive behaviours by comparing a fished and unfished spawning aggregation site and tracking responses over time at the fished site. Using observational sampling and predator exposure experiments, we analysed fear responses (flight initiation distance, return time), as well as time spent in vigilance, courtship and territorial defence. Unpaired males at fished sites were twice as likely to flee from simulated predators and took longer to return to mating territories. In contrast, paired males at both sites took greater risks during courtship, fleeing later than unpaired males, but returned earlier at the unfished site compared with the fished site. Our findings suggest that high fishing pressure reduces reproductive opportunities by increasing vigilance and compromising territorial defence, potentially affecting mate selection cues. Altered behavioural trade-offs may mitigate short-term capture risk but endanger long-term population survival through altered reproductive investment. Human extractive practices targeting animal reproductive aggregations can have disruptive effects beyond direct removal, influencing animal behaviours crucial for population survival.

Preliminary evidence of a potential reproductive aggregation area of the common stingray Dasyatis pastinaca (Linnaeus, 1758) (Chondrichthyes – Dasyatidae) in the Central Mediterranean Sea

Shallow and coastal aggregations of batoids are poorly documented in the Mediterranean Sea, despite being likely threatened by multiple anthropogenic pressures. We report the first observations of a potential summer reproductive aggregation of the common stingray (Dasyatis pastinaca). The recurrent presence in previous years of several pregnant females, a mature male and a female with fresh bite wounds was recorded in shallow waters by recreational scuba divers and scientists in Scilla Bay (Strait of Messina, Italy), a location with unique oceanographic features in the Central Mediterranean Sea. These observations suggest that the area could be used as a parturition and mating site in early summer, and this is significant for the conservation of this Vulnerable species.

Changes in the distribution density of locate, Thaisella chocolata (Duclos, 1832) (Gastropoda, Thaididae) as an indicator for predicting their reproductive events

For a population of locate, Thaisella chocolata, in La Rinconada, Chile, on a grid of 39 stations distributed along three 910 m-long transects at depths of 5 to 18.5 m, Moran and Morisita indices were used to evaluate whether density variations along the depth distribution are related to the stratification of larger sizes at the beginning of their reproductive process. Results indicate that before, during, and after forming reproductive aggregations, there is a T. chocolata increase in density in the shallow stratum (5 to 13 m). This finding is corroborated by the Moran index, which showed a greater autocorrelation in January-May, September-October, and January 2010, and by the Morisita index; thus, it is validated as a potentially easy-to-use indicator for assessing the reproductive process of this species. This index could also alert fishermen to the prevalence of reproductive aggregations in an area and that these aggregations should not be exploited as is currently the case to ensure the reproductive success of this species.

Diverse environmental cues drive the size of reproductive aggregation in a rheophilic fish

BackgroundAnimal migrations are periodic and relatively predictable events, and their precise timing is essential to the reproductive success. Despite large scientific effort in monitoring animal reproductive phenology, identification of complex environmental cues that determine the timing of reproductive migrations and temporal changes in the size of reproductive aggregations in relation to environmental variables is relatively rare in the current scientific literature.MethodsWe tagged and tracked 1702 individuals of asp (Leuciscus aspius), a large minnow species, and monitored with a resolution of one hour the size of their reproductive aggregations (counts of sexes present at the breeding grounds standardized by the sum of individuals in the season) over seven breeding seasons using passive integrated transponder tag systems. We examined the size of reproductive aggregations in relation to environmental cues of day number within a reproductive season (intra-year seasonality), water temperature, discharge, hour in a day (intra-day pattern), temperature difference between water and air, precipitation, atmospheric pressure, wind speed and lunar phase. A generalized additive model integrating evidence from seven breeding seasons and providing typical dynamics of reproductive aggregations was constructed.ResultsWe demonstrated that all environmental cues considered contributed to the changes in the size of reproductive aggregations during breeding season, and that some effects varied during breeding season. Our model explained approximately 50% of the variability in the data and the effects were sex-dependent (models of the same structure were fitted to each sex separately, so that we effectively stratified on sex). The size of reproductive aggregations increased unimodally in response to day in season, correlated positively with water temperature and wind speed, was highest before and after the full moon, and highest at night (interacting with day in a season). Males responded negatively and females positively to increase in atmospheric pressure.ConclusionThe data demonstrate complex utilization of available environmental cues to time reproductive aggregations in freshwater fish and their interactions during the reproductive season. The study highlights the need to acquire diverse data sets consisting of many environmental cues to achieve high accuracy of interpretation of reproductive timing.Graphical abstract

Sex-specific expression of pheromones and other signals in gravid starfish

BackgroundMany echinoderms form seasonal aggregations prior to spawning. In some fecund species, a spawning event can lead to population outbreaks with detrimental ecosystem impacts. For instance, outbreaks of crown-of-thorns starfish (COTS), a corallivore, can destroy coral reefs. Here, we examine the gene expression in gravid male and female COTS prior to spawning in the wild, to identify genome-encoded factors that may regulate aggregation and spawning. This study is informed by a previously identified exoproteome that attracts conspecifics. To capture the natural gene expression profiles, we isolated RNAs from gravid female and male COTS immediately after they were removed from the Great Barrier Reef. ResultsSexually dimorphic gene expression is present in all seven somatic tissues and organs that we surveyed and in the gonads. Approximately 40% of the exoproteome transcripts are differentially expressed between sexes. Males uniquely upregulate an additional 68 secreted factors in their testes. A suite of neuropeptides in sensory organs, coelomocytes and gonads is differentially expressed between sexes, including the relaxin-like gonad-stimulating peptide and gonadotropin-releasing hormones. Female sensory tentacles—chemosensory organs at the distal tips of the starfish arms—uniquely upregulate diverse receptors and signalling molecules, including chemosensory G-protein-coupled receptors and several neuropeptides, including kisspeptin, SALMFamide and orexin.ConclusionsAnalysis of 103 tissue/organ transcriptomes from 13 wild COTS has revealed genes that are consistently differentially expressed between gravid females and males and that all tissues surveyed are sexually dimorphic at the molecular level. This finding is consistent with female and male COTS using sex-specific pheromones to regulate reproductive aggregations and synchronised spawning events. These pheromones appear to be received primarily by the sensory tentacles, which express a range of receptors and signalling molecules in a sex-specific manner. Furthermore, coelomocytes and gonads differentially express signalling and regulatory factors that control gametogenesis and spawning in other echinoderms.

Limiting factors for queen conch (Lobatus gigas) reproduction: A simulation-based evaluation.

Queen conch are among the most economically, socially, and culturally important fishery resources in the Caribbean. Despite a multitude of fisheries management measures enacted across the region, populations are depleted and failing to recover. It is believed that queen conch are highly susceptible to depensatory processes, impacting reproductive success and contributing to the lack of recovery. We developed a model of reproductive dynamics to evaluate how variations in biological factors such as population density, movement speeds, rest periods between mating events, scent tracking, visual perception of conspecifics, sexual facilitation, and barriers to movement affect reproductive success and overall reproductive output. We compared simulation results to empirical observations of mating and spawning frequencies from conch populations in the central Bahamas and Florida Keys. Our results confirm that low probability of mate finding associated with decreased population density is the primary driver behind observed breeding behavior in the field, but is insufficient to explain observed trends. Specifically, sexual facilitation coupled with differences in movement speeds and ability to perceive conspecifics may explain the observed lack of mating at low densities and differences between mating frequencies in the central Bahamas and Florida Keys, respectively. Our simulations suggest that effective management strategies for queen conch should aim to protect high-density reproductive aggregations and critical breeding habitats.

A safe haven for potential reproductive aggregations of the critically endangered Brazilian guitarfish (Pseudobatos horkelii).

Brazilian endemic batoid elasmobranch populations have declined dramatically in the past 40 years due to anthropic activities (e.g., overfishing). The Brazilian guitarfish, Pseudobatos horkelii, included in the IUCN red list of endangered species [Critically Endangered (CR)], has been captured as by-catch by trawling fishing boats to the edge of extinction. Despite governmental conservation initiatives, the species is still caught and commercialized along the Brazilian coast. In this study, the authors report three rare aggregation events for the Brazilian coast of P. horkelii, inside the only nearshore no-entry Brazilian marine protected area. Strategies for its protection are also discussed.

Steller Sea Lion (Eumetopias jubatus) at Tuleny Island, Russia in Autumn 2018: Abundance, Composition, and Entanglement.

The Steller sea lion (SSL, Eumetopias jubatus) inhabits the North Pacific Ocean off both the North American and Asian coasts. The abundance of the species in Asia declined by more than half in the second part of the 20th century. Decline recurred in the second decade of the 21th century after a short period of restoration. In contrast with the total dynamics of SSL in Asia, the reproductive aggregation on Tuleny I. (Sea of Okhotsk) has been growing almost continuously since the beginning of its formation in the late 1980s. Long-term monitoring of SSL at Tuleny I. always covered only summer reproductive seasons. We surveyed Tuleny I. in October 2018, and counted 1058 non-pup sea lions and 396 pups. The majority of tagged animals encountered at the rookery were of local origin. About one-third of the summer non-pup sea lions' number could remain at the rookery until the middle of October, which coincides with the seasonal appearance of sea lions off the coast of Japan. The sex-age structure was characterized by total absence of adult males and reduced proportion of subadult males and juveniles. It contrasts with autumn behavior of SSLs in the rookery of the northern Sea of Okhotsk. We observed that 0.7% of the inspected sea lions were entangled in marine debris. The proportion of entangled animals is lower in comparison with that of the whole population of Tuleny I. due to reduction in the ratios of males and juveniles, which entangle in foreign objects more often than adult females.

Spawning aggregation sites of the cubera snapper, Lutjanus cyanopterus, on the continental shelf of Bahia state, Northeastern Brazil

The cubera snapper (caranha), Lutjanus cyanopterus, is an important resource for reef fisheries in Northeastern Brazil, currently classified as Vulnerable (VU) on the Red List of Threatened Species. This species forms large transient reproductive aggregations, concentrating their reproductive efforts in a short period of the year and in specific spawning sites, which have already been well documented in the Caribbean. These aggregations are predictable in time and space, making them considerably vulnerable to overfishing and other sources of anthropic impacts. These tend to reduce the population’s renewal capacity and genetic diversity, thus contributing to the decline of fish stocks and to the process of local extinctions. Between 2009 and 2010 we identified two L. cyanopterus aggregation sites, commonly known as “Caranheiros”, in two sub-areas located at the continental shelf-break zone of Bahia state, Northeastern Brazil, in the East Brazil Shelf Large Marine Ecosystem (LME16), between latitudes 12 °S and 15 °S. The present study aims to (1) describe patterns of spatial and temporal distribution, and the biological characteristics of L. cyanopterus’ catches from line fisheries targeting the specific aggregations in the two Caranheiros sites; and (2) validate the reproductive character of these aggregations through macroscopic evaluation of sexual maturity phases of the fishes caught. We analyzed fisheries and biological sampling data from the catches of artisanal fleets monitored in the two sub-areas between 2005 and 2014. The identified aggregations occur annually from December to May, with capture peaks concentrated in waning to waxing moon phases, in January, February and March. The predominance of mature, pre-spawning and spent (recent spawning) individuals, males and females, in these aggregations revealed the reproductive activity in both sites. Identifying and validating these spawning sites may contribute to the development of recovery and conservation plans for this threatened species. The continuous monitoring of fisheries on aggregations is a priority, aiming to trigger management responses and adaptative fisheries management. Considering these sites are highly vulnerable and have high local socioeconomical importance, especially to traditional fishers, the exact location of the analyzed “Caranheiros” is not revealed in this publication. However, it has been made available to the government agencies responsible for fisheries control and surveillance, as well as for implementing management and conservation measures for the sustainable use of fisheries resources.

Modeling the bottom temperature variation patterns on a coastal marine ecosystem of the Southwestern Atlantic Ocean (El Rincón), with special emphasis on thermal changes affecting fish populations

Abstract The detailed knowledge of temperature variation patterns in marine ecosystems is important to understand marine communities' dynamics. The present study modeled the historical (1980–2016) daily bottom temperatures on a shallow marine ecosystem of the Southwestern Atlantic Ocean (El Rincon), which is a reproductive ground for several commercially important fish. A detailed description of bottom temperature variation patterns was performed mainly focusing on those changes influencing fish populations. The model used in the present study is a modification from previous models applied to lakes and tidal inlets, and predicts daily water temperatures from air temperatures and radiation, considering in turn the change of thermal inertia with depth. Bottom temperature data for model calibration, and also salinity, were recorded on 666 oceanographic stations between July 1993 and December 2012. More than 95% of daily bottom temperature variation was explained by the fitted model, and predictability decreased from 98 to 82% in relation to the increase in thermal inertia with depth. High model deviations (>1.5 °C) were associated with a particular salinity range (33.6–33.9) and evidenced eventual occurrence of cold water advections more evident during the warm season. In response to the changes in thermal inertia with depth, the seasonal occurrence of two opposite horizontal thermal gradients was evident each year. These gradients involved a shoreward warming during the warm season, which promotes fish reproductive aggregations, and a shoreward cooling (warming toward deeper zones) during the cold season, which is related with adult fish dispersion or even migration. Up to more than one month of difference in the onset-end pattern of these thermal gradients was observed depending on the year. Long-term linear variation trends in temperature changed seasonally, with higher cooling rates during spring months, which was particularly evident during October. Also, irregular 3 to 7 year thermal oscillations appeared to occur, indicating the influence of one or more climate variability phenomena. These results depict the general dynamics of bottom temperature patterns in a shallow temperate marine ecosystem, with particular emphasis on their implications for understanding different aspects of fish populations. Particularly, the model and specific data provided in this study will help to further advance our knowledge of this marine ecosystem, in which fishes play an important economical role.

Determination of catchability-at-age for the Mexican Pacific shrimp fishery in the southern Gulf of California

One of the main problems in the sequential Mexican-shrimp fisheries is the use of a constant catchability coefficient for fleets exploiting different population components implying a constant vulnerability in the population structure over time and age which denies important population processes and causes bias in fishery model outputs. The purpose of this study was to determine the catchability-at-age (qa,t)coefficients in time and across ages the sequential shrimp fishery fleets exploiting white, blue and brown shrimp in the southern Gulf of California. The qa,t values were able to identify the catchability patterns in time and across ages for each fleet, denoting important population processes (e.g. migration, recruitment and reproduction) per species. The qa,t values of the inshore fleet were three orders of magnitude lower than those from the offshore fleet in the white shrimp, showing an increase in the inshore fishing vulnerability which is associated to subadult migrations. The qa,tfor the offshore fleets were found to be of similar magnitude among species with the highest observed values in the brown shrimp. However, their patterns showed differential peaks of recruitment to the marine fishery and reproductive aggregations. For the blue and brown species, the increment in their vulnerability could be associated to the offshore fishery recruitment and the reproductive aggregations, observing an increase in the qa,t values in relation to the first maturity ages. The integration of the qa,t variability over time and across ages into the Mexican management of the shrimp fishery could improve the harvest rates and aid to reduce the growth and/or recruitment overfishing for the southern Gulf of California.

Analysis of an astounding aggregation of Ranzania laevis (Molidae: Actinopterygii) in the tropical south-western Atlantic.

Unusual catches of more than 4200 kg of the slender sunfish Ranzania laevis are described from the south-western Atlantic, corresponding to the largest aggregation records for the species. These unexpected records were associated with unusually warm currents in the area. Males and females were physiologically able to spawn at the moment of capture, suggesting the occurrence of reproductive aggregation in this species.

The masquerade game: marine mimicry adaptation between egg-cowries and octocorals

Background. Background matching, as a camouflage strategy, is one of the most outstanding examples of adaptation, where little error or mismatch means high vulnerability to predation. It is assumed that the interplay of natural selection and adaptation are the main evolutionary forces shaping the great diversity of phenotypes observed in mimicry; however, there may be other significant processes that intervene in the development of mimicry such as phenotypic plasticity. Based on observations of background mismatching during reproduction events of egg-cowries, sea snails of the family Ovulidae that mimic the octocoral where they inhabit, we wondered if they match the host species diversity. Using observations in the field and molecular systematics, we set out to establish whether the different egg-cowrie color/shape polymorphisms correspond to distinct lineages restricted to specific octocoral species.Methods. Collection and observations of egg-cowries and their octocoral hosts were done using SCUBA diving between 2009 and 2012 at two localities in the Tropical Eastern Pacific (TEP), Malpelo Island and Cabo Corrientes (Colombia). Detailed host preference observations were done bi-annually at Malpelo Island. We analyzed the DNA sequence of the mitochondrial genes COIand 16S rDNA, extensively used in phylogenetic and DNA barcoding studies, to assess the evolutionary relationship among different egg-cowrie colorations and morphologies.Results. No genetic divergence among egg-cowries associated to different species of the same octocoral genus was observed based on the two mitochondrial genes analyzed. For instance, all egg-cowrie individuals from the two sampled localities observed on 8 different Pacifigorgia-Eugorgia species showed negligible mitochondrial divergence yet large morphologic divergence, which suggests that morphologies belonging to at least two sea snail species, Simnia avena(=S. aequalis) and Simnialena rufa, can cross-fertilize.Discussion. Our study system comprised background-matching mimicry, of the masquerade type, between egg-cowries (Simnia/Simnialena) and octocorals (Pacifigorgia/Eugorgia/Leptogorgia). We observed mimicry mismatches related to fitness trade-offs, such as reproductive aggregations vs. vulnerability against predators. Despite the general assumption that coevolution of mimicry involves speciation, egg-cowries with different hosts and colorations comprise the same lineages. Consequently, we infer that there would be significant tradeoffs between mimicry and the pursuit of reproductive aggregations in egg-cowries. The findings of this study not only contribute to the understanding of the evolution of mimicry in egg-cowries, a poorly studied group of marine gastropods, but also to the development of a new biologically meaningful board game that could be implemented as a learning tool.

Diploid males of Scaptotrigona depilis are able to join reproductive aggregations (Apidae, Meliponini)

The sex determination system in the eusocial stingless bees (Apidae, Meliponini) is based on the combination of alleles at the complementary sex determination (CSD) locus. In this system, males are haploid and females are diploid. However, diploid males can develop from fertilized eggs when they are homozygous at single or multiple sex loci. The production of such males can negatively affect population viability, since they are usually infertile or inviable. Moreover, when they are viable but infertile, or siring sterile triploid offspring, this could cause another load on the population, leading the fertilized offspring of other females to be only haploid males or triploid sterile daughters. In this context, our aim was to verify whether diploid males of the stingless beeScaptotrigonadepilisdo in fact join reproductive aggregations. We showed that of 360 marked males from two different colonies, five were participating in a reproductive aggregationca.20 meters from their natal colonies. Using microsatellites markers, it was confirmed that three of these five males were diploid. They were captured in the mating aggregations when they were 15 to 20 days old. Further research is necessary to determine the mating success of stingless bee diploid males under natural conditions and to determine their impact on stingless bee population extinction risks.

Diploid males of Scaptotrigona depilis are able to join reproductive aggregations (Apidae, Meliponini)

The sex determination system in the eusocial stingless bees (Apidae, Meliponini) is based on the combination of alleles at the complementary sex determination (CSD) locus. In this system, males are haploid and females are diploid. However, diploid males can develop from fertilized eggs when they are homozygous at single or multiple sex loci. The production of such males can negatively affect population viability, since they are usually infertile or inviable. Moreover, when they are viable but infertile, or siring sterile triploid offspring, this could cause another load on the population, leading the fertilized offspring of other females to be only haploid males or triploid sterile daughters. In this context, our aim was to verify whether diploid males of the stingless bee Scaptotrigona depilis do in fact join reproductive aggregations. We showed that of 360 marked males from two different colonies, five were participating in a reproductive aggregation ca. 20 meters from their natal colonies. Using microsatellites markers, it was confirmed that three of these five males were diploid. They were captured in the mating aggregations when they were 15 to 20 days old. Further research is necessary to determine the mating success of stingless bee diploid males under natural conditions and to determine their impact on stingless bee population extinction risks. JHR 45: 125–130 (2015) doi: 10.3897/JHR.45.4769 http://jhr.pensoft.net Copyright Ayrton Vollet-Neto et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. SHORT COMMUNICATION Ayrton Vollet-Neto et al. / Journal of Hymenoptera Research 45: 125–130 (2015) 126

An alien in the group: eusocial male bees sharing nonspecific reproductive aggregations.

Sexual selection predicts that individuals competing for access to sexual partners should maximize their chances of mating by looking for sites where the chances of finding partners are more likely to occur. However, males of stingless bees have been observed sharing nonspecific reproductive aggregations. This uncommon behavior appears to confer no obvious increase of individual fitness. It has been suggested that this reproductive strategy is due to the similarity between male odors common to different stingless bee species. Cuticular hydrocarbons (CHCs) are candidate odors of interest because their nonvolatile pheromone nature allows them to play an important role in sexual behavior and species recognition. Here, we review the literature to evaluate whether any phylogenetic patterns exist among male stingless bees that aggregate with closely or distantly related species. We also compared the CHC profiles of males of Neotropical stingless bee species (Plebeia sp. Schwarz, Trigona spinipes (F.), Tetragona clavipes (F.), Nannotrigona testaceicornis (Lepeletier), Scaptotrigona aff. depilis (Moure), Tetragonisca angustula (Latreille), and Melipona subnitida (Ducke) to reveal any chemical similarities among their male odors. We found males of 21 stingless bee species involved in interspecific interactions mainly from Neotropical and Indo-Malayan/Australasian regions. Alien males did not necessarily visit host aggregations of closely related species. Furthermore, the CHC profiles of different studied species were very distinct from each other and do not overlapped at all. It is unclear yet why this apparently nonadaptive behavior carried out by some stingless bee males.

Results on photo identification for beluga whale <i>Delphinapterus leucas</i> in the Anadyr estuary of the Bering Sea

Definition of individual beluga whales by the method of photo identification and selection of the main types of markers are presented for beluga whales in the Anadyr estuary, western Bering Sea. The study was conducted in the aggregation of beluga whales in three different sites at Anadyr - in the Anadyr sea port and at ferry docks № 8 and № 10 in the period from August 14 to September 6, 2013 (summer feeding of the whales). The maximum number of whales (40-70 animals) was observed at the ferry dock № 10, 2-6 whales were at the ferry dock № 8, and 1-2 ones - at the port. Mother-calf pairs were observed in all sites, but the portion of adult whales was the highest at the ferry dock № 10. Photocamera Nikon D90 and Nikkor lens (70-200 mm) were used for the photo ID. Mechanical skin damages, infections, spinal ridge traces, and age spots were used as individual markers. In total, 4400 images were obtained, including 155 ones with sides of beluga whales. The markers were observed both on the left side (32 cases) and right side (97 cases) of the whales, but both sides were identified for 13 whales only, including 3 females with calves. Taking into account the risk of reassessment in case of using two sides for identification, the identification is considered as successful for 110 individuals of beluga whale. Almost all identified individuals were met only once during the whole period of observation, only 6 of them were met twice, and only 4 - three times. One whale appeared 3 days in a row: on August 16, 17 and 18, and 5 individuals came 2 days in a row. Such few recurrent meetings may indicate a weak fidelity of beluga whales to certain water areas in the estuary, though maybe the length of study is insufficient, taking into account that a strong fidelity of mother-calf pairs of beluga whales to certain areas of the Anadyr estuary, considered as their hunting areas, was determined by visual observations of Shirshov Institute of Oceanology in the 1980s. Probably, the area at the dock № 10, where the whales form large aggregation, is not assigned to individual animals but is a common feeding area. This large aggregation is similar to the aggregation of beluga whales at Cape Beluzhy of Solovetsky Island in the White Sea. However, these aggregations are fundamentally different by their nature: the reproductive aggregation at Solovetsky Island is distinguished by various forms of social interactions, including sexual activity, while the search and hunting behavior prevail in the feeding aggregation at the ferry dock № 10. The main reason for the beluga whales concentration in this area is dense concentration of freshwater fish and salmons migrating for spawning. Reproductive aggregations of beluga whales are not known yet in the Far-Eastern Seas.

Experiência de monitoramento participativo a bordo de embarcações da pesca artesanal no Território da Cidadania do Baixo Sul da Bahia, Brasil

O monitoramento participativo e amostragem biológica realizada por pescadores artesanais, a bordo de suas embarcações, foi conduzida entre janeiro de 2011 a maio de 2012 no Território da Cidadania do Baixo Sul da Bahia. A abordagem adotada teve como objetivo incluir os pescadores no processo de pesquisa, valorizando o conhecimento tradicional e garantindo também a aquisição de dados biológicos de difícil acesso, sobre a desova de peixes recifais capturados em sítios de agregação reprodutiva distantes da costa. A ação foi desenvolvida a partir da integração de pescadores colaboradores no âmbito da pesquisa. Dois mestres da pesca de linha, reconhecidos como especialistas nas comunidades de Valença e Camamu, foram beneficiados com bolsas de pesquisa pela Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB). Os mestres e tripulação das embarcações consideradas foram qualificados e envolvidos no monitoramento, coletando informações sobre captura, esforço e área de pesca (pesqueiros), realizando biometria, coleta de gônadas e determinação de estádios de maturação sexual. Os pescadores colaboradores foram acompanhados por pesquisadores e técnicos da Universidade Estadual de Feira de Santana (UEFS) e da Empresa Baiana de Desenvolvimento Agrícola (EBDA). Foram monitoradas 56 pescarias realizadas em 24 pesqueiros, contemplando 3.271 peixes medidos e pesados, pertencentes a 26 grupos taxonômicos populares, além da coleta de 149 gônadas. A avaliação da abordagem foi baseada em parâmetros qualitativos: 1) engajamento e colaboração na atividade e 2) eficácia e coerência na coleta dos dados, preenchimento das fichas e classificação das gônadas. A percepção dos pescadores quanto a relevância do monitoramento participativo para promoção da construção de conhecimentos sobre a atividade pesqueira e da dinâmica reprodutiva dos recursos pesqueiros constitui o principal desafio da abordagem proposta. Uma ação continuada é considerada fundamental para o desenvolvimento crítico individual dos envolvidos e fortalecimento dos laços de confiança estabelecidos entre pescadores, técnicos e pesquisadores, assim como para a indicação de ações que promovam a conservação e uso sustentável dos recursos naturais.

Synoptic oceanography of San Jorge Gulf (Argentina): A template for Patagonian red shrimp (Pleoticus muelleri) spatial dynamics

An extensive series of high-resolution satellite images from the advanced very high-resolution radiometer (AVHRR) and the sea-viewing wide field-of-view sensor (SeaWIFS) was used in a synoptic oceanographic characterization of San Jorge Gulf (SJG, Argentine Patagonia), an area of great significance for marine conservation and commercial fishing. Remotely sensed information was combined with on-board observer's data and published information to investigate the role of distinctive oceanographic features in relation to the life cycle of the Patagonian red shrimp (Pleoticus muelleri), main target of the industrial fleet in SJG. Three frontal systems—North, South and Outer SJG—are characterized. The North and South SJG fronts are associated with shrimp reproductive aggregations during late spring and summer. While both function as spawning/nursery grounds, they differ from each other in many respects. The thermohaline South SJG front has its maximum expression during the winter, reflecting the influence of the low-salinity Magellanic Plume, while the thermal North SJG front develops during spring and summer as the water column becomes stratified in the central basin of the gulf. Wind-related down-welling inshore of the front prevails in the North SJG, and upwelling in the South SJG frontal area. Chlorophyll a is concentrated near the thermocline on the stratified side of the North SJG, and for that reason, it is not detected by remote sensors during the spring bloom and the summer but becomes apparent offshore from the location of the front when the thermocline deepens during the fall (May). In the South SJG front, Chl-a concentration is apparent inshore from the front all year-round, related in part to upwelling-mediated resuspension. The northern end of the outer front coincides in time and space with a recurrent non-reproductive aggregation of red shrimp between November and January and is presumably related to foraging. It is argued that keeping the North and South SJG frontal systems off-limits to fishing is a central precautionary requisite for the sustainability of the shrimp fishery.

Local ecological knowledge of the artisanal fishers on Epinephelus itajara (Lichtenstein, 1822) (Teleostei: Epinephelidae) on Ilhéus coast--Bahia State, Brazil.

BackgroundLocal Ecological Knowledge (LEK) of traditional fishermen may be the only source of information regarding the conservation of the marine ecosystem and its endangered species. One of these species is Epinephelus itajara, which can exceed 2 m in length and 400 kg weight, is classified by the IUCN as a critically endangered. In Brazil, there is currently a moratorium that prohibits the capture of this specie, and in the northeastern coast, a Marine Protected Area was recently established properly justified by the existence a one spawning aggregation. The scope of the present study was the analysis the LEK of fishers with the goal of contributing to the conservation of E. Itajara.MethodsThe Knowledge of 24 “experts” was recorded through semi-structured interviews with fishermen selected based on their expertise. LEK regarding some aspects of the life history of E. itajara, such as its morphology, spatial distribution, feeding, breeding and conservation, was systematized. The interviews were conducted in synchronic and diachronic situations. The data analysis followed the model of unity of the various individual skills, while the consistency of the analysis was tested using a matrix of methods employed in comparative cognitive science. Potential reproductive aggregation sites were identified by experts through projective interviews conducted based on a cartographic database and transferred to a geographic information system (GIS).ResultsThe LEK of these specialists in relation to the biological and ecological characteristics of E. itajara showed a high level of detail and a high agreement with the scientific literature. Projective interviews are presented as a promising tool allowing spatialization of the information generated through the registration of LEK. Therefore, the visualization of information from the fishermen, as well as its analysis and comparison with other databases, is simplified, thereby contributing to the decision-making process concerning the conservation of marine ecosystem in Brazil.ConclusionsIntegration of LEK with scientific knowledge is an efficient strategy for the conservation of endangered species, as it provides important additional biological information that can be used in the process of participative and sustainable management of marine resources.