Lutjanus Synagris Research Articles

Interactions between Northern-Shifting Tropical Species and Native Species in the Northern Gulf of Mexico

Niche models applied in the context of future climate change predict that as regional temperatures increase, the distribution of tropical species will shift poleward. While range expansions have been documented for a number of species, there is limited information on the ecological impacts of shifts on native species. Recently, abundances of tropically-associated gray snapper (Lutjanus griseus) and lane snapper (Lutjanus synagris) have increased in seagrass nurseries in the northern Gulf of Mexico (GOM), concurrent with regional increases in sea surface temperature. We investigated effects of increased abundances of these species on abundance and growth of pinfish (Lagodon rhomboides), the dominant native species. Because juvenile pinfish and snappers share common prey, predators, and habitat, the high degree of niche overlap suggests an equally high potential for competition. We used a multiple before–after control impact design to determine whether increased snapper abundances significantly affected abundance or growth of pinfish. Trawl surveys at six locations in the northern GOM in summer and fall 2010 were used to calculate pinfish and snapper abundances. We identified three locations with high snapper abundances and three locations with no snapper and compared pinfish abundance and otolith-determined growth rates in these locations before and after snapper recruitment. Paired t tests and two-way analysis of variance revealed no significant differences in pinfish abundance or growth in the presence of snappers compared to locations and seasons without snappers. We conclude that range expansions of tropically associated snappers have had no significant effect on abundance or growth of native pinfish in northern GOM seagrass habitats.

A barcode for the authentication of the snappers (Lutjanidae) of the western Atlantic: rDNA 5S or mitochondrial COI?

The increasing demand for fishery resources in recent years has stimulated a growth in the output of processed products, which has made the fraudulent substitution of species a common practice. In the present study two different protocols were evaluated for the molecular authentication of lutjanid species, one based on the banding pattern of the nuclear rDNA 5S gene, and the other on the sequences of the mitochondrial Cytochrome Oxidase subunit I (COI) gene. A total of 132 samples were analyzed from specimens identified previously as belonging to seven lutjanid species (Lutjanus purpureus, Lutjanus synagris, Lutjanus vivanus, Lutjanus jocu, Lutjanus analis, Ocyurus chrysurus, and Rhomboplites aurorubens), as well as unidentified individuals. The results indicate the absence of a species-specific rDNA 5S banding pattern in lutjanids. However, the 1131 bp fragment of the COI gene not only discriminated the identified lutjanid species systematically, but also defined the species of the unidentified specimens, identifying another two species from the database, Lutjanusbucanella and Lutjanuscyanopterus. The species were represented by well-defined consensual clades in the phylogenetic trees, supported by the interspecific distances and the mutations characteristic of each species. This segment of the COI gene proved to be a robust tool for the molecular authentication of lutjanid species.

Ocorrência de Crustáceos Ectoparasitos no Peixe Ariacó, Lutjanus synagris (Linnaeus, 1758) nas Águas Costeiras do Rio Grande do Norte, Brasil

O ariacó, Lutjanus synagris é um peixe marinho de grande valor comercial que contribui para a produção pesqueira artesanal do Rio Grande do Norte, Brasil. O presente estudo investigou a ocorrência de crustáceos ectoparasitos no peixe marinho L. synagris no litoral do Rio Grande do Norte. Foram capturados 100 exemplares de L. synagris nas águas costeiras do Rio Grande no Norte, no período de março de 2008 a fevereiro de 2009.

Selective mortality during the larval and juvenile stages of snappers (Lutjanidae) and great barracuda Sphyraena barracuda

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 474:227-242 (2013) - DOI: https://doi.org/10.3354/meps10114 Selective mortality during the larval and juvenile stages of snappers (Lutjanidae) and great barracuda Sphyraena barracuda E. K. D’Alessandro*, S. Sponaugle, R. K. Cowen Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, USA *Email: edalessa@rsmas.miami.edu ABSTRACT: Selective mortality during the early life stages in marine organisms can affect the magnitude and composition of recruitment, yet these processes have not been examined in economically important predatory coral reef fishes. Utilizing 3 different stage-specific sampling techniques (shipboard plankton tows, larval light traps, juvenile surveys/seines), we repeatedly sampled multiple cohorts of 3 lutjanid (Ocyurus chrysurus, Lutjanus synagris, and L. griseus) and 1 sphyraenid (Sphyraena barracuda) species through time in the Florida Keys (USA). Comparisons of daily growth and size-at-age (from otolith microstructure analysis) for early- and late-stage larvae and young and older juveniles revealed that size- and growth-selective processes operate during the larval stage, while after settlement, growth-selective mortality occurred in the absence of significant size differences. In all 3 lutjanid species, larvae and juveniles that were larger at hatch preferentially survived. In O. chrysurus and L. synagris, selective mortality of smaller, slower-growing individuals during the larval stage reduced variability in these traits such that larvae were of similar sizes at settlement. Following settlement, patterns of growth-selective mortality were initially opposite (favoring faster juvenile growth in L. synagris, and slower growth in O. chrysurus), but ultimately survivors of both species grew faster, leading eventually to a size advantage. In contrast, patterns of selective mortality were not evident until settlement in L. griseus and S. barracuda, and favored larger and smaller sizes-at-settlement, respectively. Overall, our results reveal important patterns of selective mortality and variability between even closely related species. KEY WORDS: Ocyurus chrysurus · Lutjanus synagris · Lutjanus griseus · Growth-mortality hypothesis · Coral reef fishes Full text in pdf format Supplementary material PreviousNextCite this article as: D’Alessandro EK, Sponaugle S, Cowen RK (2013) Selective mortality during the larval and juvenile stages of snappers (Lutjanidae) and great barracuda Sphyraena barracuda . Mar Ecol Prog Ser 474:227-242. https://doi.org/10.3354/meps10114 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 474. Online publication date: January 31, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.

Cryogenic preservation of sperm from lane snapper (Lutjanus synagris): Testing the effects of extenders and freezing rates on sperm quality

In this study, we assess the feasibility of cryopreservation of L. synagris sperm for short- (10days) and long-term (12month) storage using a combination of intracellular (DMSO or MeOH) and extracellular (egg yolk or milk) cryoprotectants, and two freezing protocols. Milt was mixed with a cryogenic solution (8% extracellular cryoprotectant, and 5%, 8%, 10% or 12% intracellular cryoprotectant) to a ratio of 1:2 (milt: medium), stored in 0.5mL French straws and frozen using two protocols for each experiment: a Slow freezing curve (dry ice–nitrogen liquid vapor–liquid nitrogen, ca. 15°C−min) and a Fast freezing curve (dry ice–liquid nitrogen, ca. 30°C−min), for 10minutes during each stage. Milt was then thawed in an ambient temperature water bath (28–30°C). Activation of thawed milt was effective with either saline (450nM NaCl) or bicarbonate (3.5% NaHCO3) solutions, but the best results were obtained with artificial sea water (ASW) at 870mOsmol/kg. After 10days or 12months of storage, three-factor interactions were found between extenders, cryoprotectant concentrations and the two freezing curves for movement duration, % motility and % viability. All of the three post-thaw sperm components assessed were two to three times greater for the DMSO trials than for the MeOH trials. There was almost no difference in sperm viability and motility between the DMSO extenders with egg yolk or milk after 10days or 12months. Greater short- and long-term spermatozoa survival and post-thaw motility were found when semen was diluted 1:2 with extenders of 10% DMSO, 8% egg yolk/milk and 1% Ringer Solution, using a three-step cooling regime with a freezing rate of ca. −15°C−min. This study represents the first report of cryopreservation of L. synagris sperm, however further research is needed to improve the effectiveness of the cryopreservation protocol for broad-scale application, taking into account the effects of French straws of greater volume on cooling and freezing rates, and the effect of different thawing rates on spermatozoa properties and fertilization success.

The Paraty artisanal fishery (southeastern Brazilian coast): ethnoecology and management of a social-ecological system (SES).

This study intends to give recommendations to the management of Paraty fishery in Brazil through an interplay of local and scientific knowledge. In particular, the objectives are the following: 1) to describe the Paraty fishery; 2) to compare the fishermen’s local ecological knowledge with recorded fish landings and previous studies in Paraty; 3) to combine the data on local fishing and on local/Caiçara livelihoods with the SES (social-ecological systems) Model. The methods include a systematic survey of fishing in Tarituba and Praia Grande, which are located in the northern end and the central part of the Paraty municipality, respectively. For four days each month, systematic data on catches at landing points were collected, as well as macroscopic gonad analysis data for the fishes Centropomus parallelus and C. undecimalis (snook, robalo), Epinephelus marginatus (grouper, garoupa), Scomberomorus cavalla (King mackerel, cavala), and Lutjanus synagris (Lane snapper, vermelho). Spring and summer are important seasons during which some species reproduce, and the integration of fishing periods for some target species could assist in fishing management through the use of closed seasons. Fishermen could obtain complementary earnings from tourism and from the “defeso system” (closed season including a salary payment) to conserve fishing stocks. The SES model facilitates an understanding of the historical context of fishing, its economic importance for local livelihoods, the constraints from conservation measures that affect fishermen, and the management processes that already exist, such as the defeso. If used to integrate fishing with complementary activities (tourism), such a system could improve the responsibility of fishermen regarding the conservation of fish stocks.

Evidence of multiple vicariance in a marine suture‐zone in the Gulf of Mexico

AbstractAim Our aim was to assess whether single or multiple vicariance event(s) have occurred in a marine suture‐zone in the northern Gulf of Mexico. We estimated the divergence time of two genetically distinct groups of lane snapper (Lutjanus synagris), distributed on either side of this zone, and compared it to the timing of other vicariance events described previously in the area.Location The northern Gulf of Mexico from the Texas coastline to the Atlantic coast of South Florida, USA. The marine suture‐zone is proximal to Mobile Bay in Alabama.Methods A Bayesian Markov chain Monte Carlo (MCMC) approach was used to estimate mutation‐corrected divergence and genetic migration between eastern and western groups of lane snapper, based on genotypic differences at 13 nuclear‐encoded microsatellites obtained previously from 77 and 171 individual samples, respectively. A second estimate of divergence time for eastern and western groups of lane snapper was generated, based on 590 base pairs of DNA sequence from the mitochondrially encoded NADH dehydrogenase subunit 4 (ND4) obtained previously from 45 and 93 individual samples, respectively.Results Both classes of genetic markers (microsatellites and mtDNA) indicated a fairly recent divergence. Confidence intervals for microsatellite‐based estimates suggested that divergence began less than 21 thousand years ago (ka), while confidence intervals for mitochondrial DNA‐based estimates suggested divergence began less than 130 ka. These estimates were not consistent with vicariance events in the literature, which are hypothesized to have occurred well before 135 ka.Main conclusions These results indicate that the marine suture‐zone in the northern Gulf of Mexico features multiple vicariance events and may be characterized by a complex geological/environmental history. We suggest that processes during or after the Wisconsin glaciation (c. 110–18 ka) may have created a previously unrecognized barrier for lane snapper and possibly other species as well.

Sex Ratio and Length-Weight Relationship for Five Marine Fish Species from Brazil

Sex Ratio and Length-Weight Relationship for Five Marine Fish Species from Brazil This study estimated the sex ratio and length-weight relationships for five marine fish species, Mugil curema (Valenciennes, 1836), Chloroscombrus chrysurus (Linnaeus, 1766), Opisthonema oglinum (Lesueur, 1818), Hemiramphus brasiliensis (Linnaeus, 1758) and Lutjanus synagris, (Linnaeus, 1758) from the Brazilian coastal waters. Fish were collected on monthly basis by local fishermen using diversified fishing gears, such as, beach seine net, ballyhoo fishing net, gillnets and hand lines. The population of Mugil curema showed the expected ratio of 1:1. However, predominance of male C. chrysurus, O. oglinum and L. synagris, and females of H. brasiliensis were recorded. In general, the b exponent ranged from 2.6243 (C. chrysurus) to 3.3647 (L. synagris). The results indicated a negative allometric growth for the species O. oglinum and C. chrysurus, and an isometric growth for M. curema and H. brasiliensis. Moreover, an isometric and a positive allometric growth were recorded for females and males of L. synagris.

Food habits of the lane snapper, Lutjanus synagris (Perciformes: Lutjanidae), in the north zone of the Colombian Caribbean

This work describes the food habits of Lutjanus synagris by means of stomach content analysis, considering the trophic spectrum in general as well as by sex and size, the ecological aspects of the preys, their spatial distribution, and the relationship of the diet with the habitat conditions. In the analysis of 148 stomachs 45.3% were found to be full and 54.7% empty. The most representative preys (%N) were: Portunus spp. (27.3 %; n = 44) and Squilla intermedia (10.6%; n = 17), whereas the gravimetric analysis (%P) showed the heaviest preys to be Gastropoda (31.8%; 51.74 g) and Farfantepenaeus spp. (17.5%; 28.52 g). The frequency of occurrence (%FO) showed that Portunus spp. (25.4%; 17 stomachs) and S. intermedia (10.5%; 7 stomachs) were the most frequent preys. According to the IRI (%), Portunus spp. (43.01%) and Gastropoda (13.38%) were the most representative categories. The diet of L. synagris was found to consist of four types of main preys: Portunidae (837.06), Gastropod (260.29), Squillidae (234.66), and Penaeidae (218.05); and two types of secondary preys: Sicyoniidae (126.35) and Trichiuridae (75.64); with all others being incidental preys. The spatial distribution of the breadth of the trophic niche and the size of L. synagris allowed us to identify two zones. The first, between Riohacha and Dibulla, had the highest niche breadth values (0.64-1.00), denoting generalist predators, and the smallest specimens of L. synagris. The second zone, between Riohacha and Punta Gallinas, had the lowest niche breath values (0.00-0.23), indicating a high degree of dietary specialization, and the largest-sized individuals.

Genetic Divergence and Effective Size among Lane Snapper in U.S. Waters of the Western Atlantic Ocean

AbstractPopulation structure of lane snapper Lutjanus synagris in U.S. waters in the northern Caribbean Sea was assessed using nuclear‐encoded microsatellites and mitochondrial DNA (mtDNA) from samples from four localities in the U.S. Caribbean and one locality in the Florida Keys. Significant heterogeneity was detected for both allele and genotype distributions (microsatellites) and for haplotype distribution (mtDNA). Pairwise comparisons revealed that fish in the Florida Keys differed significantly from fish in the U.S. Caribbean with respect to both microsatellites and mtDNA. A parsimony network of mtDNA haplotypes was consistent with division of the five sample localities into two distinct populations. Genetic diversity at both microsatellites and mtDNA was greater among fish from the Florida Keys. The average, long‐term migration rate from the U.S. Caribbean westward to the Florida Keys was approximately 1.75‐fold greater than the reverse, suggesting that the elevated genetic variability among fish from the Florida Keys reflects the westward movement of alleles as a function of westward‐flowing surface currents in the region. Bayesian coalescent analysis (microsatellites) indicated that each of the two populations has experienced a 10‐fold decline in effective population size (Ne). Estimates of long‐term effective size, generated using a coalescent, maximum‐likelihood method, were 1,671.9 (Florida Keys) and 2,923.2 (U.S. Caribbean). Estimates of contemporaneous effective size, generated using a linkage‐disequilibrium approach with minor alleles (those with frequencies of 0.02 or less) being excluded, were 275.6 (Florida Keys) and 668.9 (U.S. Caribbean) and differed significantly from one another. Because the samples contained mixed cohorts, the short‐term estimates reflect the effective number of breeders (Nb) that produced the cohort(s) from which the samples were taken. The difference between the long‐term and short‐term estimates of Ne (or Nb) suggests that the declines in the effective size of both populations are relatively recent and that management concern over lane snapper in the Florida Keys is justified.Received July 23, 2010; accepted December 14, 2010

Ethnobiology of snappers (Lutjanidae): target species and suggestions for management

In this study, we sought to investigate the biology (diet and reproduction) and ethnobiology (fishers knowledge and fishing spots used to catch snappers) of five species of snappers (Lutjanidae), including Lutjanus analis, Lutjanus synagris, Lutjanus vivanus, Ocyurus chrysurus, and Romboplites saliens at five sites along the northeast (Riacho Doce, Maceió in Alagoas State, and Porto do Sauípe, Entre Rios at Bahia State) and the southeast (SE) Brazilian coast (Paraty and Rio de Janeiro cities at Rio de Janeiro State, and Bertioga, at São Paulo State.).We collected 288 snappers and interviewed 86 fishermen. The stomach contents of each fish were examined and macroscopic gonad analysis was performed. Snappers are very important for the fisheries of NE Brazil, and our results indicated that some populations, such as mutton snapper (L. analis) and lane snapper (L. synagris), are being caught when they are too young, at early juvenile stages.Local knowledge has been shown to be a powerful tool for determining appropriate policies regarding management of target species, and artisanal fishermen can be included in management processes. Other suggestions for managing the fisheries are discussed, including proposals that could provide motivation for artisanal fishermen to participate in programs to conserve resources, such as co-management approaches that utilize local knowledge, the establishment of fishing seasons, and compensation of fishermen, through 'payment for environmental services'. These suggestions may enhance the participation of local artisanal fishermen in moving to a more realistic and less top-down management approach of the fish population.

Ichthyofauna in an estuary of the Mataripe area, Todos os Santos Bay, Bahia, Brazil

The community structure and dynamics as well as some biological parameters of selected species of the ichthyofauna of the Mataripe estuarine region affected by the Landulfo Alves Oil Refinery (RLAM) were analyzed. Twenty stations were sampled with a gillnet in five different periods: August and December 2003, March and July/August 2004 and January 2005. Thirty-five actinopterygian species and one elasmobranch species were recorded, Oligoplites saurus, Diapterus rhombeus, Lutjanus synagris and Scomberomorus brasiliensis among them, on all the campaigns. A total of 1368 specimens, weighing 36.10 kg, were caught. The ichthyofauna total biomass was greater, in weight, on the eastern side of the study region, especially at the stations close to the shoals/reefs and the rocky bottom. A similar pattern was also observed for the diversity values. In general, low evenness and diversity were observed in the area studied, possibly as a result of the fishing gear used. D. rhombeus juveniles dominated in all but one of the samplings (July 2004), in which latter Cyclichthys spinosus was dominant. Carangids and species associated with consolidated bottoms were observed, although in small numbers, throughout the study period. In spite of the limitations imposed by the gear used for sampling, the estuarine area influenced by the RLAM was seen to play a role as a growth area for the great majority of species, especially the mojarra (D. rhombeus), but it offers no fishing potential due to the prevalence of young and small individuals. Evidence of imminent spawning was recorded for Pomadasys corvinaeformis in August 2003, and recent spawning in March 2004 for Oligoplites saurus. Further, mature individuals occurred in insufficient numbers to permit population level evaluation.

Spawning patterns of commercially important reef fish (Lutjanidae and Serranidae) in the tropical western South Atlantic

Although information on the spawning seasons of commercially important snappers (Lutjanidae) and groupers (Serranidae, subfamily Epinephelinae) is available for the north and central west Atlantic, there is little information for the tropical western South Atlantic (Brazil). As a consequence, there are few fishery regulations in this entire region that take into consideration such information. In this study, we characterized the reproductive cycles of three Epinephelinae serranids ( Epinephelus morio, Mycteroperca bonaci and Cephalopholis fulva ) and five lutjanids ( Lutjanus synagris, L. jocu, L. analis, Ocyurus chrysurus and Rhomboplites aurorubens ) that occur in the Abrolhos Bank, Brazil, the largest reef complex in the tropical western South Atlantic. A total of 3528 gonads were collected from May 2005 to October 2007. Temporal variability in spawning patterns was evaluated using the Gonadosomatic Index (GSI) and macroscopic analyses. The peak of reproductive activity for the three grouper species occurred between July and August. Snappers exhibited two peaks of reproductive activity, the more intense of which occurred between September and October. The other peak occurred between February and March, with the exception of the deep-dwelling species R. aurorubens , which only reproduced between February and March. Seasonal patterns were consistent over the two consecutive years that we studied, and these patterns are equivalent to those observed for the Northern Hemisphere, as are the sizes at maturity and at the time of sexual change (for the three protogynous hermaphrodite groupers). Fisheries management in this region could be significantly improved by a combination of catch and effort limitations being imposed during spawning seasons and by overall size limitations, particularly considering that most of the fish caught are generally below size at maturity. The proposed buffer zones for the marine areas that are presently protected in Abrolhos represent an opportunity for implementing both spatial (e.g. setting no-take zones that cover spawning sites) and temporal (e.g. seasonal closures during spawning peaks) management tools, using a participatory approach at the regional scale.

Feeding ecology of the estuarine dolphin (Sotalia guianensis) on the coast of Rio Grande do Norte, Brazil

AbstractWe analyzed the stomach contents of 40 estuarine dolphins, Sotalia guianensis (van Benédén 1864), beached on the coast of Rio Grande do Norte, Brazil, between February 2000 and February 2007. A total of 223 prey items were identified, including 18 species of teleosts and 5 species of cephalopods. The index of relative importance (IRI) showed that Larimus breviceps, Haemulon plumieri, Lutjanus synagris, Trichiurus lepturus, Mugil curema, and Diapterus rhombeus were the six most important species. The IRI showed that L. breviceps was the main prey for both adults and the young. H. plumieri was the most important for the males and T. lepturus for the females. Seven species of teleosts and two of cephalopods were recorded in the diet of estuarine dolphins for the first time in the country. Our results suggest that the estuarine dolphin can be a feeding specialist and that foraging activity occurs mainly in estuarine areas, where the animals can use passive listening to detect prey.

Diet and food partitioning between juveniles of mutton Lutjanus analis, dog Lutjanus jocu and lane Lutjanus synagris snappers (Perciformes: Lutjanidae) in a mangrove‐fringed estuarine environment

Diet of juvenile mutton Lutjanus analis, dog Lutjanus jocu and lane Lutjanus synagris snappers were studied in the tropical Brazilian estuarine system of the Piraquê-açú and Piraquê-mirim Rivers to determine how these species share the resources in this restricted space. The three species prey principally upon Peracarida (L. synagris: relative importance index I(RIc) = 29%), Natantia (L. analis and L. synagris: I(RIc) = 39 and 38%, respectively), Reptantia (L. analis and L. jocu: I(RIc) = 28 and 43%, respectively) and Teleostei (L. jocu: I(RIc) = 24%). The three species use estuaries as nursery habitats but food overlap was not biologically significant due to a combination of interspecific differences in size, spatial distribution, microhabitat preferences and seasonal patterns of abundance and prey choice. Large marine protected areas incorporating essential habitats for all life stages are suggested to be the best tool for the management of these economically important species.

Trypsin from the Processing Waste of the Lane Snapper (Lutjanus synagris) and Its Compatibility with Oxidants, Surfactants and Commercial Detergents

A trypsin from the viscera of the lane snapper (Lutjanus synagris) was purified by heat treatment, fractionation with ammonium sulfate and affinity chromatography. The molecular weight of the enzyme was estimated to be 28.4 kDa (SDS-PAGE). The purified enzyme was capable of hydrolyzing the specific substrate for trypsin benzoyl-arginine-p-nitroanilide (BApNA) and was inhibited by benzamidine and tosyl lysine chloromethyl ketone (TLCK), synthetic trypsin inhibitors and phenylmethylsulfonyl fluoride (PMSF), which is a serine-protease inhibitor. The enzyme exhibited maximal activity at pH 9.0 and 45 degrees C and retained 100% of the activity after incubation at the optimal temperature for 30 min. At a concentration of 10 mM, activity was slightly activated by Ca(2+) and inhibited by the following ions in decreasing order: Cd(2+) > Hg(2+) > Cu(2+) > Zn(2+) > Al(3+). The effects of Ba(2+), K(1+) and Li(1+) proved to be less intensive. Using 1% (w/v) azocasein as substrate, the enzyme revealed high resistance (60% residual activity) when incubated with 10% H(2)O(2) for 75 min. The enzyme retained more than 80% activity after 60 min in the presence of different surfactants (Tween 20, Tween 80 and sodium choleate). The alkaline protease demonstrated compatibility with commercial detergents (7 mg/mL), such as Bem-te-vi, Surf and Ala, retaining more than 50% of initial activity after 60 min at 25 degrees C and 30 min at 40 degrees C. The thermostability and compatibility of this enzyme with commercial detergents suggest a good potentiality for application in the detergent industry.

Hábitos alimenticios del pargo rayado, Lutjanus synagris (Perciformes: Lutjanidae), en la zona norte del Caribe colombiano

This work describes the food habits of Lutjanus synagris by means of stomach content analysis, considering the trophic spectrum in general as well as by sex and size, the ecological aspects of the preys, their spatial distribution, and the relationship of the diet with the habitat conditions. In the analysis of 148 stomachs 45.3% were found to be full and 54.7% empty. The most representative preys (%N) were: Portunus spp. (27.3 %; n = 44) and Squilla intermedia (10.6%; n = 17), whereas the gravimetric analysis (%P) showed the heaviest preys to be Gastropoda (31.8%; 51.74 g) and Farfantepenaeus spp. (17.5%; 28.52 g). The frequency of occurrence (%FO) showed that Portunus spp. (25.4%; 17 stomachs) and S. intermedia (10.5%; 7 stomachs) were the most frequent preys. According to the IRI (%), Portunus spp. (43.01%) and Gastropoda (13.38%) were the most representative categories. The diet of L. synagris was found to consist of four types of main preys: Portunidae (837.06), Gastropod (260.29), Squillidae (234.66), and Penaeidae (218.05); and two types of secondary preys: Sicyoniidae (126.35) and Trichiuridae (75.64); with all others being incidental preys. The spatial distribution of the breadth of the trophic niche and the size of L. synagris allowed us to identify two zones. The first, between Riohacha and Dibulla, had the highest niche breadth values (0.64-1.00), denoting generalist predators, and the smallest specimens of L. synagris. The second zone, between Riohacha and Punta Gallinas, had the lowest niche breath values (0.00-0.23), indicating a high degree of dietary specialization, and the largest-sized individuals.

Climate‐related, decadal‐scale assemblage changes of seagrass‐associated fishes in the northern Gulf of Mexico

AbstractGlobal temperatures are rising, and are expected to produce a poleward shift in the distribution of many organisms. We quantified changes in fish assemblages within seagrass meadows of the northern Gulf of Mexico (GOM) between the 1970s and 2006–2007, and observed changes consistent with this forecast. During 2006–2007 we sampled seagrass meadows using the same gears and methods previously employed by R. J. Livingston in coastal waters of northwest Florida throughout the 1970s. Comparisons between datasets revealed numerous additions to the fish fauna during 2006–2007 that were completely absent in the 1970s, including: Lutjanus synagris (lane snapper), Epinephelus morio (red grouper), Chaetodon ocellatus (spotfin butterflyfish), Mycteroperca sp (grouper, non gag), Centropristis philadelphica (rock sea bass), Fistularia tabacaria (bluespotted cornetfish), Ocyurus chrysurus (yellowtail snapper), Thalassoma bifasciatum (bluehead wrasse), Abudefduf saxatilis (sergeant major), Acanthuridae spp. (surgeonfishes) and Sparisoma viride (stoplight parrotfish). Several other species showed large increases in abundance during the interval between 1979 and 2006, including Mycteroperca microlepis (gag grouper, up ∼200 ×), Lutjanus griseus (gray snapper, up ∼105 ×), and Nicholsina usta (emerald parrotfish, up ∼22 ×). All of these are tropical or subtropical species that now make up a greater percentage of seagrass‐associated fish assemblages in the northern GOM than in the past. Additionally, we observed regional increases in air and sea surface temperatures (> 3 °C) during the ∼30 years that separate Livingston's samples and ours that correlate with northern shifts in the distribution of warm‐water fishes. Documenting these range shifts is a critical first step in investigating the consequences of global warming for endemic marine communities and fishery production in the northern GOM.

Avaliação da qualidade nutricional em espécies de pescado mais produzidas no Estado da Bahia

Diversos fatores podem contribuir para a variabilidade na composição das diferentes espécies de pescado. Este trabalho teve como objetivo, identificar as espécies de pescado mais produzidas no Estado da Bahia, avaliar seu valor nutricional e realizar um levantamento das empresas beneficiadoras de pescado do Estado. Um questionário foi aplicado às beneficiadoras de pescado para a caracterização das empresas. Segundo a Bahia Pesca (2005), as espécies mais produzidas são: o camarão-rosa (Penaeus brasiliensis), representando 21,8% da produção estadual; a sardinha (Opisthonema oglinum), 10,2%; os vermelhos com as espécies guaiúba (Ocyurus chrysurus) e o ariacó (Lutjanus synagris), 6,6%; seguidos pela tainha (Mugil spp.), 4,1%. De acordo com o valor nutricional das espécies analisadas, a guaiúba foi considerada melhor para o consumo, por possuir menor teor de lipídios totais (0,82%) e gordura saturada (28,74%). A produção de 43% das beneficiadoras de pescado do Estado da Bahia está entre 10 e 50 ton/mês e a principal dificuldade apresentada foi a falta de investimento do governo no setor.

Genetic analysis of Lutjanus synagris populations in the Colombian Caribbean

Species of the family Lutjanidae constitute an important fishery resource in tropical marine areas worldwide and are intensely exploited because of their excellent commercial value and quality. In Colombia, the lane snapper Lutjanus synagris is considered vulnerable to overfishing due to its biological characteristics, habitat deterioration, and historical decrease in catch rates in regions where it used to comprise the highest percentage of the landings. In order to generate more biological information needed to make effective fishery management decisions and policies, the genetic structure of L. synagris was analyzed in three areas of the Colombian Caribbean (Santa Marta, Rosario Islands, and Capurganá) using microsatellite-type molecular markers. Fourteen primers reported for two phylogenetically close species (Rhomboplites aurorubens and Lutjanus campechanus) were analyzed, eight of which were polymorphic and informative for the species under study. All loci were found to depart from Hardy-Weinberg equilibrium due to marked heterozygote deficiency in all the populations studied. Both the analysis of molecular variance (total population ΦST = 0.006, P = 0.022) and spatial analysis of molecular variance showed a slight statistically significant population structure (best FCT = 0.003, ΦST = 0.007, P = 0.0001) that separated the Capurganá population from those of the other areas with no evidence of isolation by distance (Mantel test Rxy = 0.023, P = 0.057). The results suggest that the life history of the species and the regional oceanographic conditions play an important role in determining the genetic structure and the existence of two different genetic stocks that should be managed according to their population structure.