Fish Spawning Aggregation Sites Research Articles

Acoustic telemetry provides insights for improving conservation and management at a spawning aggregation site of the endangered Nassau grouper (Epinephelus striatus)

Nassau grouper (Epinephelus striatus, Serranidae) were one of the most important fishery species in the Caribbean, but are now listed as critically endangered. Population collapse in most places occurred primarily by fishers targeting their spawning aggregation sites, where thousands of fish gathered during full moon periods from December to April. Identifying management options for protecting this vulnerable period is crucial for their survival. In the US Virgin Islands, we tagged 24 Nassau grouper with acoustic transmitters at a fish spawning aggregation (FSA) site called the Grammanik Bank, a 1.5 km2, marine protected area (MPA) closed each year from February to April. We tracked their movements over a seven-year period and found that the small MPA protected Nassau grouper only 65% of time during the spawning season. Nassau grouper arrived at the FSA from January to May, with a peak in March, and made daily roundtrip migrations (1-25 km) from the FSA site. Females swam twice as far as males, while males were more sedentary and remained longer (22 d) at the FSA than females (9 d); behavioural characteristics that may cause differential bycatch mortality among sexes. We also found nearly half of all fish were temporary residents within 5 km of the FSA site for 2 to 6 months after the spawning season. This mismatch of MPA size and timing of closed season provided the impetus for developing new guidelines for protection. The large acoustic array allowed us to calculate spatially relevant areas useful for conservation including courtship arena (1.2 km2), staging area (4.7 km2) and primary migration pathways (9.6 km2) used by Nassau grouper during spawning season. To improve conservation goals of this endangered species, increasing the Grammanik Bank seasonal closure to five months and its size to 6.4 km2 would increase protection to >96%. These spatial and temporal changes to existing management regulations incorporate the best available data to improve conservation goals by reducing potential bycatch mortality, eliminating disturbance of spawning fish, and protecting critical spawning habitat for Nassau grouper. These guidelines may also be applied more broadly to other Nassau grouper FSA sites located on large insular or continental shelfs areas throughout the Caribbean.

Spawning aggregation of bigeye trevally, Caranx sexfasciatus, highlights the ecological importance of oil and gas platforms

There is growing interest in understanding the ecological benefits of oil and gas structures. This is the first reported case of the spawning aggregation and mating behaviour of bigeye trevally, Caranx sexfasciatus, associated with an oil and gas platform, demonstrating that oil and gas jackets are capable of not only attracting large aggregations of fish, but can provide suitable conditions for reproductive purposes. Fish spawning aggregations (FSAs) are highly vulnerable events that are vitally important for the persistence of many fish species. Urgent protection and conservation of FSA sites is required to secure them from the threat of overfishing. The findings of this study bring into question the management strategies required for oil and gas structures, particularly related to removal during decommissioning, or where structures are left in place and safety exclusion zones no longer apply. These aggregations and behaviours were captured using underwater stereo-video Remotely Operated Vehicle (ROV) methods, allowing for detailed observations.

Coastal oceanographic conditions during a cold front passage over a fish spawning aggregation site located in the Mesoamerican Reef

In this study, an observational campaign that included measurements of coastal currents and thermohaline structure on a fish aggregation reef site during 11–17 March 2017 is analyzed. For the period of the present study, we observed the response of the coastal oceanographic conditions to meteorological forcing. In particular, we described the effects of the cold front passage (locally called a “Norte”) on the water column over a fish aggregation reef site. Before the passage of the Norte, the site was exposed to NE - SE Trade winds, stratification of the water column and sea surface currents moved mainly northward in the alongshore component and offshore in the cross-shore component. However, during the passage of the cold front or Norte, there were changes in the wind field, temperature and atmospheric pressure. Norte conditions were associated with strong northerly winds and with a continuous drop in air temperature. This atmospheric forcing resulted in an evolution of the oceanographic conditions at the reef site from that observed during Trade winds. It changed from stratified to a well-mixed water column, and then dense water on the shallow reef area resulted by cooling and evaporation due to the extreme weather condition during Nortes. This dense water descends down the inner-shelf with density contrast of 0.52 kg/m3 producing a near bottom offshore flow (below 15 m depth). Thus, weather conditions have a determinant role in coastal currents and in the thermohaline structure in the fish aggregation reef site.

Passive acoustics as a tool to quantify/characterize vessel activity at fish spawning aggregation sites

The vulnerability of fish spawning aggregations (FSA) to fishing pressure has led to seasonal fishing bans for certain aggregating reef-fish species and seasonal or permanent closures of known FSA sites throughout the Caribbean. While discerning the degree of compliance with fisheries regulations is essential in evaluating their success, this information can be scarce when opportunistic surveillance from enforcement vessels is minimal or absent. We used passive acoustic recorders to determine the temporal patterns of vessel activity at three red hind, Epinephelus guttatus, spawning aggregation sites off western Puerto Rico with varying levels of protection (Buoy 4: no regulation, Abrir la Sierra (ALS): seasonal closure, and Mona: permanent closure) during the closed (January and February) and open (March) periods for the capture of red hind. We proposed that dynamic vessel sounds (e.g., gear shifting, sudden changes in speed) at known FSA sites and during aggregating periods could be indicative of fishing activity. A band-limited energy detector was used to detect vessel sounds, with detections grouped into discreate vessel events and classified as having only constant vessel sounds or containing dynamic vessel sounds. While most of the vessel events consisted of constant vessel sounds at all sites, events with dynamic vessel sounds were greatest at Buoy 4, followed by ALS and only one detected at Mona. Average events with dynamic vessel sounds were greater during the closed than the open period at Buoy 4, while the opposite was found at ALS, and red hind calling activity was significantly correlated with vessel detections during 3 years at Buoy 4. Results suggest fishers may have been targeting red hind at Buoy 4 despite red hind's seasonal closure, and the site-specific regulations at ALS may have served as a deterrent and divert fishing effort towards other areas. Acoustic records can reveal high-resolution temporal patterns of vessel activity and of events with dynamic vessel sounds, which could be used to infer about fishing activities and complement other surveys to provide estimates of compliance.

Grouper Tales: Use of Acoustic Telemetry to Evaluate Grouper Movements at Western Dry Rocks in the Florida Keys

AbstractThe Western Dry Rocks (WDR) area off Key West, Florida, is an open fishing area that contains a multispecies fish spawning aggregation site, but grouper spawning there has yet to be confirmed. The movements of 18 adult and subadult grouper at WDR were tracked using acoustic telemetry to determine how this area is used by grouper species and whether it contains a grouper spawning aggregation site. Tagged fish consisted of 10 Black Grouper Mycteroperca bonaci, 5 Nassau Grouper Epinephelus striatus, 2 Gag M. microlepis, and 1 Yellowfin Grouper M. venenosa. Overall, tagged grouper were more likely to be present in the WDR array during winter spawning months, with species‐specific seasonal differences. Our results indicated that grouper presence increased during spawning months, although some adults and subadults were present year‐round. Grouper made more movements per day during non‐spawning months compared to spawning months, although the north side of WDR was the most heavily used area, regardless of the time of year. Additionally, spatial graphs of grouper movement suggested that different grouper species utilized different areas of WDR. Increased presence of grouper during spawning months suggests that the WDR area may contain a grouper spawning aggregation site, which would mean that fish species aggregate to spawn at this location year‐round. The success of the Florida Keys fisheries critically depends on the protection of multispecies spawning aggregations like that potentially contained at WDR.

Drivers of male sound production and effective communication distances at fish spawning aggregation sites

AbstractWhile monitoring fish sounds has enhanced our understanding of spatio-temporal patterns of spawning and acoustic communication, data interpretation often fails to account for environmental effects on acoustic recordings, resulting in uncertainty of whether measures of detected fish sounds correspond to rates of sound production, specific behaviours, and abundance. In this study, we applied acoustic propagation modelling and detection theory to estimate rates of sound production of territorial, male Gulf grouper (Mycteroperca jordani) from passive acoustic recordings and evaluate effective communication distances. To assess behavioural drivers, environmentally calibrated, hourly estimates of sound production rates were compared to diver observations of courtship, spawning, and numbers of females encountered within male territories. Rates of sound production increased before sunset and were correlated to observed rates of spawning and females encountered, indicating that sound production is largely driven by female presence and increased opportunities to spawn. The mean effective communication distance was estimated to be <21 m, supporting the importance of short-range communication within the observed behaviours. Our findings corroborate that fish sounds can be used to infer measures of reproductive activity and the relative abundance of both sexes during spawning periods once properly calibrated for environmental effects and detection capabilities.

Fish Spawning Aggregations Dynamics as Inferred From a Novel, Persistent Presence Robotic Approach

Fish spawning aggregations (FSA) consist of the temporary gathering of a large number of fishes at a specific location to spawn. Monitoring of FSA is typically conducted by divers, but surveys are often restricted to a limited area and dependent upon sea conditions, thus our knowledge of FSA dynamics is extremely limited. Fisheries independent research strives for new technology that can help remotely and unobtrusively quantify fish biomass and abundance. Since some fish species, such as groupers, produce sounds during reproductive behaviors, Eulerian passive acoustic monitoring provides information when divers cannot access the FSA site. Fish sounds provide an innovative approach to assess fish presence and potentially their numbers during reproductive events. However, this technology is limited by the sound propagation range, hence the distance between the fish emitting sounds the hydrophone location. As such, this Eulerian monitoring approach implicitly creates a knowledge gap about what happens beyond the range of the recorders. Furthermore, the large datasets make the detection process by human ears and eyes very tedious and inconsistent. This paper reports on two innovative approaches to overcome these limitations. To facilitate fish call detections, we have developed an algorithm based on machine learning and voice recognition methods to identify and classify the sounds known to be produced by certain species during FSA. This algorithm currently operates on a SV3 Liquid Robotics wave glider, an autonomous surface vehicle which has been fitted to accommodate a passive acoustic listening device and can cover large areas under a wide range of sea conditions. Fish sounds detections, classification results, and locations along with environmental data are transmitted in real-time enabling verification of the sites with high detections by divers or other in-situ methods. Recent surveys in the US Virgin Islands with the SV3 Wave Glider are revealing for the first time the spatial and temporal distribution of fish calls surrounding known FSA sites. These findings are critical to understanding the dynamics of fish populations because calling fish were detected several kilometers away from the known FSAs. These courtship associated sounds from surrounding areas suggest that other FSAs may exist in the region.

Reproductive biology and behavior associated with a spawning aggregation of the yellowfin grouper Mycteroperca venenosa in the US Virgin Islands

The reproductive characteristics, movement patterns and courtship behaviors associated with a yellowfin grouper (Mycteroperca venenosa, Linnaeus, 1758) fish spawning aggregation (FSA) were assessed between 2004 and 2014. The FSA was located on the Grammanik Bank, a seasonally closed area on the edge of the Puerto Rico platform, south of St. Thomas, US Virgin Islands. Fish arrived at the FSA site around full moon and departed 10–12 days after full moon (dafm), during two or three consecutive months, from January to May each year. Males were significantly larger than females and preceded females at the spawning site. Courtship coloration and behaviors showed distinct patterns relative to lunar date and time of day. Spawning was observed for several days each month in 2008, 2009, 2011 and 2014, from 6 to 10 dafm. Female gonadosomatic index (GSI) values were highest from 4 to 7 dafm. Spawning, which began at sunset, consisted of 7 to 12 males following one female along the bottom before ascending 10–20 m, then "rushing" upward to release gametes. Histological analysis of ovaries indicated females spawned every 2–3 nights, although 11.6% were capable of spawning two consecutive nights. Total spawning population size of yellowfin grouper fluctuated from 600 to 1100 fish during the study period, but consistent annual population assessments using scuba were difficult to carry out due to ocean conditions. Based on size-frequency analysis and other metrics, the M. venenosa spawning population at the Grammanik bank appears to be stable at this time with existing regulations.

Should we protect extirpated fish spawning aggregation sites?

Some locations have extraordinary ecological and conservation significance and subsequently need protection to guarantee the persistence of species that depend on them. Fish Spawning Aggregation (FSA) sites, where fish congregate to breed, are examples of such places, but are being extirpated worldwide through overfishing. Although transient FSA sites figure prominently as priority areas for conservation, extirpated aggregations, that due to current low abundance at spawning times are no longer recognizable as FSAs, represent a dilemma for managers. Given the limited resources available for conservation actions, should we protect extirpated FSAs or omit them from spatial management plans? Here we present two contrasting points of view, look into the mechanisms associated with the emergence and maintenance of aggregation sites, and review available evidence of recovery in the field. Of the 53 extirpated FSA sites examined, 9 (17%) reported recovery, always after strict management was implemented. All recovered sites were located in the wider Caribbean and western Atlantic. We make the case that extirpated FSAs seem to have the potential to recover and their protection may provide a cost effective way to help rebuild fisheries. It is unclear, however, if a remnant population is needed to allow recovery. Current methods used to monitor and assess FSA status and extirpation are not consistent, hindering site trend analysis, between-site comparisons and meta-analysis. We suggest that monitoring and management should be made more consistent and strengthened to boost FSA recovery.

Cooperative monitoring, assessment, and management of fish spawning aggregations and associated fisheries in the U.S. Gulf of Mexico

Many species of inshore, coastal, and reef fishes in the U.S. Gulf of Mexico (GOM) aggregate to spawn at specific sites and times. These fish spawning aggregations (FSAs) can be highly vulnerable to concentrated fishing pressure, which can have detrimental effects on entire stocks and ecosystems. There has been only limited research and management attention on FSAs in the U.S. GOM. We synthesized available information on FSA locations, spawning seasonality, and fisheries management for 28 regionally important species known or likely to form FSAs in the U.S. GOM. We identified and mapped 22 multi-species FSA sites which all fall within areas predicted from recently published FSA distribution models. But the number of known sites is probably far less than the number that actually exist. Only three of the 22 (13%) FSA sites were located within no-take marine protected areas and none were in state waters. Management measures (e.g., seasonal closures or gear restrictions) to protect spawning fishes are also limited, particularly in state waters. We recommend expanded cooperative research efforts to characterize FSAs in the U.S. GOM in order to assist managers in prioritizing sites and seasons for additional protection. Important multi-species FSAs can be incorporated in a network of monitored and managed “sentinel” sites. These efforts should build stakeholder engagement in the management process, generate data that can be used to improve fisheries stock assessments, contribute to developing ecosystem-based fisheries management approaches, and confer resilience to important fisheries stocks and ecosystems of the U.S. GOM.

Grouper (Epinephelidae) spawning aggregations affect activity space of grey reef sharks, Carcharhinus amblyrhynchos, in Pohnpei, Micronesia.

Fish spawning aggregations (FSA) act as biological hotspots that concentrate food and nutrients across a broad trophic spectrum. In Pohnpei (Federated States of Micronesia), 20 female grey reef sharks (Carcharhinus amblyrhynchos) were acoustically tagged at two multi-species grouper (Epinephelidae) FSA to examine the likelihood that these mesopredators utilize FSA as a seasonal food source. Both FSA sites are within small-scale MPAs, thus providing a secondary opportunity to examine their conservation potential during these ephemeral events. Shark movement and residency was gauged against known spatial and temporal grouper reproductive patterns using an array of 15 and 50 acoustic receivers at Ant Atoll and Pohnpei (Island), respectively. Activity space was investigated using Kernel Density estimates of individual sharks, and residency indices (RI) were analyzed based on daily and monthly occurrence at the array. Three distinct residency patterns were identified: transient, semi-transient, or resident (Daily RI <0.40, >0.40 to 0.80, or >0.80, respectively). Generalized linear mixed models (GLMMs) were used to identify biological and environmental factors influencing shark activity space, including month, temperature, shark size, spawning month, and residency pattern. Findings revealed significant changes in average monthly residency indices and kernel densities during spawning months in support of an opportunistic foraging strategy around FSA. Monthly residency was higher during spawning months among semi-resident and transient sharks, while average monthly activity space was concentrated around FSA. Best-fit models for the GLMM indicated that activity spaces were most influenced by month and grouper spawning month. Seven of 20 sharks demonstrated inter-island movement and wide variations in individual movement and spatial requirements were shown. The concentration of sharks and groupers at unprotected FSA sites increases their vulnerability to fishing and supports the need for combined area and non-area management measures to effectively protect these species.

Marine Conservation Outcomes are More Likely when Fishers Participate as Citizen Scientists: Case Studies from the Mexican Mesoamerican Reef

Small-scale fishers on Caribbean coral reefs have exploited fish spawning aggregations (FSAs) for generations, but intense fishing has led to the loss of traditional aggregation sites. In many areas, the traditional ecological knowledge (TEK) of fishers has contributed greatly to the characterization of spawning aggregations and implementation of local conservation initiatives. TEK has identified more than 40 potential FSA sites along the coast of the Mexican Mesoamerican Reef. These sites have been characterised and scientifically validated, in some cases with traditional western science and in others, with a participatory citizen-science approach. The objective of this work is to compare the science and conservation outcomes at these FSA sites. We report that those FSA sites where scientific surveys were conducted without community participation remain unprotected. By contrast, the FSAs where local fishers were engaged in characterization and subsequent monitoring are now protected at the behest of the fishers themselves. Conservation initiatives to protect FSAs can be more effective through a combination of TEK, western science, and participatory citizen science involving local fishers.

Prioritizing monitoring and conservation efforts for fish spawning aggregations in the U.S. Gulf of Mexico

In the U.S. Gulf of Mexico (U.S. GOM), the identification and characterization of transient fish spawning aggregation (FSA) sites is recognized as a regional priority for conservation, but progress is hindered by a lack of understanding of FSA distributions for most exploited species. We employed information compiled in regional databases on FSAs and monitoring for the U.S. GOM to fit species distribution models and produce maps showing the areas likely to host single- and multi-species transient FSA sites. Our results revealed two distinct regions of the U.S. GOM for prioritizing monitoring and conservation efforts for transient FSAs: the coastal waters surrounding major bay systems, particularly those of Texas and Louisiana, and portions of the continental shelf edge (the Flower Garden Banks area and the West Florida shelf edge). The next step would be to locate and characterize actual transient FSA sites in the U.S. GOM by surveying within the areas we identified.

Patterns of biophonic periodicity on coral reefs in the Great Barrier Reef

The coral reefs surrounding Lizard Island in the Great Barrier Reef have a diverse soundscape that contains an array of bioacoustic phenomena, notably choruses produced by fishes. Six fish choruses identified around Lizard Island exhibited distinctive spatial and temporal patterns from 2014 to 2016. Several choruses displayed site fidelity, indicating that particular sites may represent important habitat for fish species, such as fish spawning aggregations sites. The choruses displayed a broad range of periodicities, from diel to annual, which provides new insights into the ecology of vocalising reef fish species and the surrounding ecosystem. All choruses were affected by one or more environmental variables including temperature and moonlight, the latter of which had a significant influence on the timing and received sound levels. These findings highlight the utility of passive acoustic tools for long-term monitoring and management of coral reefs, which is highly relevant in light of recent global disturbance events, particularly coral bleaching.

Fish spawning aggregations: where well‐placed management actions can yield big benefits for fisheries and conservation

AbstractMarine ecosystem management has traditionally been divided between fisheries management and biodiversity conservation approaches, and the merging of these disparate agendas has proven difficult. Here, we offer a pathway that can unite fishers, scientists, resource managers and conservationists towards a single vision for some areas of the ocean where small investments in management can offer disproportionately large benefits to fisheries and biodiversity conservation. Specifically, we provide a series of evidenced‐based arguments that support an urgent need to recognize fish spawning aggregations (FSAs) as a focal point for fisheries management and conservation on a global scale, with a particular emphasis placed on the protection of multispecies FSA sites. We illustrate that these sites serve as productivity hotspots – small areas of the ocean that are dictated by the interactions between physical forces and geomorphology, attract multiple species to reproduce in large numbers and support food web dynamics, ecosystem health and robust fisheries. FSAs are comparable in vulnerability, importance and magnificence to breeding aggregations of seabirds, sea turtles and whales yet they receive insufficient attention and are declining worldwide. Numerous case‐studies confirm that protected aggregations do recover to benefit fisheries through increases in fish biomass, catch rates and larval recruitment at fished sites. The small size and spatio‐temporal predictability of FSAs allow monitoring, assessment and enforcement to be scaled down while benefits of protection scale up to entire populations. Fishers intuitively understand the linkages between protecting FSAs and healthy fisheries and thus tend to support their protection.

Gender-specific benefits of eating eggs at resident reef fish spawning aggregation sites

Food resource availability has a fundamental role in shaping consumer populations through changes in energy intake. Tropical reef fish spawning aggregations provide a resource pulse for reef-based planktonic egg predators, and an opportunity to quantify the energetic repercussions of natural changes in food availability in tropical reef fishes. We examined the effects of the consumption of eggs from the broadcast spawning surgeonfish Ctenochaetus striatus on the allocation of energy to body condition, growth and reproduction in the planktivorous egg-predator damselfish Abudefduf vaigiensis. Fish that fed on eggs at resident fish spawning aggregation sites (FSASs) had significantly greater lipid storage in liver vacuoles compared to conspecifics from non-FSASs. Growth of male A. vaigiensis was faster at FSASs than non-FSASs. However, we found no differences in the growth of females among sites. Female A. vaigiensis from FSASs in vested more into reproduction, having larger gonadosomatic indices (GSI) than females from non-FSASs, while there was no difference in the GSI of males among FSASs and non-FSASs. At the same locations, no differences were found in the life-history traits of the reference species, Pomacentrus moluccensis, which does not consume eggs. This study demonstrates the role of natural variations in food availability on energetic processes in reef fish. Furthermore, the sex-specific energy allocation strategy highlights the complexity of the interaction between natural variations in food availability and life-history strategies. This study demonstrates that the conservation of FSASs may also benefit trophically linked reef fishes.

Spatial, temporal, and environmental dynamics of a multi-species epinephelid spawning aggregation in Pohnpei, Micronesia

Long-term and short-term underwater visual censuses using SCUBA, technical Nitrox, and closed circuit rebreathers (CCR) were carried out in Pohnpei, Micronesia, to define spatial and temporal dynamics within a semi-protected multi-species epinephelid (fish) spawning aggregation (FSA) of brown-marbled grouper, Epinephelus fuscoguttatus, camouflage grouper, Epinephelus polyphekadion, and squaretail coralgrouper, Plectropomus areolatus. Results identified species-specific patterns of habitat use, abundance, residency, and dispersal of FSAs. Fish spawning aggregations formed and dispersed monthly within a 21–160-d period after winter solstice within adjacent yet distinct outer reef habitats. The reproductive season coincided with periods of seasonally low sub-surface seawater temperature. Peaks in density varied among species both within the calendar year and relative to the winter solstice. Significant long-term declines in FSA density were observed for all three species, suggesting population-level fishery-induced impacts, similar to those previously reported for E. polyphekadion. Differences in density estimates were also observed between dive gear, with a threefold difference in densities measured by CCR for E. polyphekadion versus SCUBA that suggest a disturbance effect from exhaled SCUBA bubbles for this species. CCR also allowed surveys to be conducted over a larger area in a single dive, thereby improving the potential to gauge actual abundance and density within FSAs. Based on these findings, a combination of long-term and intensive short-term monitoring strategies is recommended to fully characterize trends in seasonal abundance and habitat use for aggregating species at single or multi-species FSA sites. Inherent variations in the timing and distribution of species within FSA make fine-scale temporal management protocols less effective than blanket protective coverage of these species at (e.g., marine protected areas covering FSAs and adjacent migratory corridors) and away from (i.e., temporal sales and catch restrictions) FSA sites.

Spawning aggregation dynamics of brown-marbled grouper and camouflage grouper at a remote Indian Ocean atoll

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 22:145-157 (2013) - DOI: https://doi.org/10.3354/esr00534 Spawning aggregation dynamics of brown-marbled grouper and camouflage grouper at a remote Indian Ocean atoll Jude Bijoux1,7,8,*, Laurent Dagorn1, Paul D. Cowley2, Monique Simier3, Pierre-André Adam4, Jan Robinson5,6 1Institut de Recherche pour Développement (IRD), UMR 212 - EME (Exploited Marine Ecosystems), PO Box 570, Victoria, Mahé, Seychelles 2South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa 3Institut de Recherche pour le Développement (IRD), UMR 212 - EME (Exploited Marine Ecosystems), Centre de Recherche Halieutique Méditerranéenne et Tropicale, Avenue J. Monnet, BP 171, 34203 Sète Cedex, France 4Island Conservation Society, Pointe Larue, Mahé, Seychelles 5Seychelles Fishing Authority, PO Box 449, Victoria, Mahé, Seychelles 6ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia 7Present address: Seychelles Fishing Authority, PO Box 449, Victoria, Mahé, Seychelles 8Present address: South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa *Email: judebijoux@gmail.com ABSTRACT: The protection of grouper spawning aggregations is a global conservation issue: populations of many grouper species are threatened with collapse due to exploitation of this critical life history behaviour by fisheries. Effective protection of spawning aggregations requires information on spawning site fidelity, residence time and timing of arrivals at, and departures from, the site. To estimate these parameters at a spawning aggregation site at Farquhar Atoll, southern Seychelles, 12 brown-marbled groupers Epinephelus fuscoguttatus and 20 camouflage groupers E. polyphekadion were tagged with acoustic transmitters, and their presence and absence was monitored by an array of acoustic receivers positioned at the site over 2 spawning seasons (2010/2011 and 2011/2012). Spawning aggregations formed during 3 consecutive spawning months each season and overlapped spatially and temporally in the 2 species. Intra- and inter-season site fidelity was high, with 91.7% of tagged E. fuscoguttatus and 89.5% of tagged E. polyphekadion detected at the site 1 yr after tagging. The majority (2010/2011: 82.4%, 2011/2012: 80.0%) of fish detected in a spawning season visited the site during at least 2 spawning months. Residence time at the fish spawning aggregation site was influenced by sex (E. fuscoguttatus only) and spawning month (both species). Distinct periodicity in lunar timing of arrivals and departures was observed in both species. This study highlights the spatio-temporal scales involved during spawning aggregations of 2 long-lived, slow-growing coral reef fishes, which need to be considered for their effective management. KEY WORDS: Spawning aggregation dynamics · Lunar and diel periodicity · Residence time · Site fidelity · Groupers · Epinephelus · Seychelles Full text in pdf format PreviousNextCite this article as: Bijoux J, Dagorn L, Cowley PD, Simier M, Adam PA, Robinson J (2013) Spawning aggregation dynamics of brown-marbled grouper and camouflage grouper at a remote Indian Ocean atoll. Endang Species Res 22:145-157. https://doi.org/10.3354/esr00534 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 22, No. 2. Online publication date: December 02, 2013 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2013 Inter-Research.

History and co-management of the artisanal mutton snapper (Lutjanus analis) spawning aggregation fishery at Gladden Spit, Belize, 1950–2011

Since the 1950s, artisanal fishers from southern Belize have harvested mutton snapper (Lutjanus analis) from the Gladden Spit fish spawning aggregation site. In 2000, the Government of Belize partnered with stakeholders to conserve the area and co-manage the fishery. The objective of this study was to present the history of the artisanal mutton snapper fishery in its environmental and socioeconomic context and qualitatively evaluate its present status. We identified long-term trends in the fishing activity through historical catch reconstructions and estimation of fishing fleet size since the late 1980s, statistically compared inter-annual trends in catch per unit effort (CPUE) and in mutton snapper sizes between 1999 and 2011, and delineated possible factors that might have caused the observed patterns. Our data show a sharp reduction in total landings and fishing effort that started in the late 1980s, parallel to a rapid growth in the tourism industry and to a shift in the livelihoods of many fishers. Annual CPUE, individual sizes, and sex ratios have been relatively stable between 1999 and 2011, indicating persistence of the fishery during this recent period. Key to successful long-term, adaptive co-management of the fishery is a continued involvement of fishers and other stakeholders in resource monitoring and evaluation, as well as in policy and decision making.

Temporal dynamics, residency and site fidelity of spawning aggregations of a herbivorous tropical reef fish Siganus sutor

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 475:233-247 (2013) - DOI: https://doi.org/10.3354/meps10113 Temporal dynamics, residency and site fidelity of spawning aggregations of a herbivorous tropical reef fish Siganus sutor Jude P. Bijoux1,*, Laurent Dagorn1, Gregory Berke2, Paul D. Cowley3, Marc Soria4, Jean-Claude Gaertner5, Jan Robinson2,6 1Institut de Recherche pour Développement (IRD), UMR 212, Victoria, Mahé, Seychelles 2Seychelles Fishing Authority, Victoria, Mahé, Seychelles 3South African Institute for Aquatic Biodiversity, Grahamstown 6140, South Africa 4Institut de Recherche pour Développement (IRD), UMR 212, Saint Denis, La Réunion 5UMR 241 EIO (UPF, IRD, Ifremer, ILM), Faaa, Tahiti, Polynésie Française 6Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia *Email: jude.bijoux@ird.fr ABSTRACT: The shoemaker spinefoot Siganus sutor is a fast-growing, short-lived, gonochorist and herbivorous reef fish that forms transient fish spawning aggregations (FSAs). In the Seychelles, FSAs of this species occur monthly between September and June around the full moon. To study the spawning aggregation dynamics of S. sutor, 39 reproductively active individuals were acoustically tagged and monitored at 3 known FSA sites (Paté Polite, Paté Désiré and Paté Dividi) off the west coast of Praslin island (Seychelles) between October 2010 and April 2011. The presence and absence of tagged fish at the 3 sites were monitored using moored arrays of passive acoustic receivers, while the density of fish at the FSAs was quantified using underwater visual census (UVC). Most tagged fish (87.0%) detected in more than 1 spawning period showed fidelity to single spawning sites. Predominantly, tagged individuals arrived at FSA sites at dawn and departed at dusk. Spawning residency times at FSA sites ranged from 0.02 to 16.1 d. At Paté Polite, residency times were higher in the first half of the spawning season. Residency times were often several-fold shorter than aggregation duration which, when combined with patterns in arrival and departure times, indicates high turnover of fish within aggregations. The findings of this study provide information needed for emerging co-management schemes that aim to sustain this socio-economically important fishery. KEY WORDS: Fish spawning aggregation · Siganus sutor · Acoustic telemetry · Residency time · Site fidelity · Seychelles Full text in pdf format PreviousNextCite this article as: Bijoux JP, Dagorn L, Berke G, Cowley PD, Soria M, Gaertner JC, Robinson J (2013) Temporal dynamics, residency and site fidelity of spawning aggregations of a herbivorous tropical reef fish Siganus sutor. Mar Ecol Prog Ser 475:233-247. https://doi.org/10.3354/meps10113 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 475. Online publication date: February 14, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.