Grouper Populations Research Articles

Potential and Risk of Grouper (Epinephelus spp., Epinephelidae) Stock Enhancement in Indonesia

Indonesia is one of the countries in Asia region that plays an important role in the grouper supply. Grouper production in Indonesia increased 5-fold within two decades aside a continuous increase in grouper demand. To enhance grouper yield, the Indonesian Government initiated stock enhancement programmes releasing cultured grouper into the natural habitats. The purpose of the present study was to examine the impact of grouper stock enhancement onto natural grouper populations in Karimujawa National Park, Indonesia and to monitor the potential risks involved. Experimental release of 10 cm cultured Epinephelus fuscoguttatus (brown-marbled grouper) from the backyard multi-species hatchery system was monitored using underwater visual census and fish-catch monitoring. As a result, it was found that the greatest peril for the released grouper of 10 cm length was falling immediately prey to predators in the reef habitat, even though enough hides were available at the release site, since groupers of this particular size class were not trained to survive under field conditions. Grouper of 15 cm however are well capable of seeking shelter and avoiding predators. This leads to the clear recommendation that released grouper should to have a size of at least 15 cm for release in stock enhancement programmes. According to our experiments the so far officially recommended minimum size of release (10 cm) is therefore too low and should be increased to 15 cm for E. fuscoguttatus, and requires future adjustment of the official recommendations in use. Parasitological examination of the released fish was conducted in order to analyse potential risks involved. No macro-parasites could be observed, limiting the risk of spreading parasites and diseases within the Indonesian archipelago. However, many parasites of E. fuscoguttatus are widespread and can infect different grouper species.

Trophic ecology of dusky grouper Epinephelus marginatus (Actinopterygii, Epinephelidae) in littoral and neritic habitats of southern Brazil as elucidated by stomach contents and stable isotope analyses

Groupers are large-bodied fishes with broad global distribution and commercial and ecological importance. Many grouper species are endangered, but information on trophic ecology of groupers outside the Mediterranean Sea is limited. We integrated stomach contents analyses (SCA) and stable isotope analyses (SIA) to test the hypotheses that diets of dusky grouper Epinephelus marginatus differ between littoral and neritic zones in the southwestern Atlantic, but exhibit similar ontogenetic shifts in prey size and consumption of fishes. SCA were dominated by fishes, crabs, and shrimp and differed significantly between habitats, but prey size and consumption of fishes increased with grouper body size at both sites. Grouper stable isotope ratios were similar between sites and among size classes, but integrating SCA and SIA distinguished ingested versus assimilated dietary components, improved dietary resolution, and provided a more comprehensive assessment of grouper in the food webs. Dusky grouper integrate benthic and pelagic trophic pathways, as well as estuarine and marine food webs via consumption of migratory prey. Our findings have applications to other threatened grouper populations, for example, in managing fragmented populations or for reserve designs considering inclusion of artificial substrates as grouper habitat, and more broadly for approaches examining trophic ecology of generalist predators.

미토콘드리아 COI 유전자 서열의 다형성과 반수체형에 근거한 한국산 붉바리(Epinephelus akaara)의 유전적 구조와 계통 유연관계

한국산 붉바리 집단에서 유전적 구조와 계통 유연관계를 mtDNA COI 유전자 서열의 다형성을 이용하여 조사하였다. COI 유전자 서열을 결정하였고 기존에 보고된 서열들과 비교하였다. 본 연구를 통해 결정된 COI 서열들은 기존에 보고된 EF607565에 대하여 99.1-99.8%의 동일성을 나타내었다. 전체 20가지의 haplotype들이 발견되었고, 한국산 붉바리 집단은 19가지의 haplotype을 나타내었다. 이들 중 Hap_03과 Hap_08은 각각 제주도와 중국-특이적인 COI 서열들을 보였다. 반면, Hap_07은 한국에서 채집된 시료들과 홍콩과 대만에서 보고된 기록 등 여러 COI 서열들을 포함하였다. COI haplotype들의 다형성에 근거한 계통 유전학적 분석을 통해 작성된 NJ tree는 Epinephelus 속 내에서 단계통적인 분지양상을 나타내었고, 이는 붉바리 집단들이 공통의 모계 선조에서 진화한 것임을 나타내었다. 또한 중국해에서 보고된 COI 서열만을 포함하였던 Hap_08은 NJ tree의 중앙부에서 위치하였고, Hap_07의 서열들과도 근연의 관계임을 보여주었다. 이 결과는 중국산 붉바리 역시 동아시아의 다른 집단들과 모계적으로 연관되어있음을 보여주었다. 결과적으로, 동아시아 붉바리 집단들은 모계적으로 연관되어있을 뿐만 아니라 공통의 진화 역사를 공유하고 있으며 여전히 동아시아 해류(Kuroshio 해류)에 의해 영향을 받는 집단이라고 할 수 있다. 본 연구는 붉바리의 유전적 구조와 계통 유연관계를 이해하는 데 도움을 줄 수 있으며, 인공증식과 산업화에 관련된 연구에 있어 중요한 역할을 담당할 것으로 기대된다. The genetic structure and phylogenetic relationship were investigated in Korean red spotted grouper populations using the nucleotide sequence polymorphisms of the mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I (COI) gene. The COI gene was sequenced showed 99.1-99.8% identity with the EF607565 sequence previously reported. A total of twenty haplotypes were found, and the Korean population showed nineteen haplotypes. Among those, Hap_03 and Hap_08 showed Jeju-do and China-specific COI sequences, respectively. However, Hap_07 had twelve COI sequences from South Korea and records from Hong Kong and Taiwan. Neighbor-joining (NJ) trees constructed from the phylogenetic analyses based on the polymorphisms of the COI haplotypes showed a monophyletic branching pattern within the genus Epinephelus. This indicated that the red spotted grouper populations had evolved from common maternal ancestors. In addition, the Hap_08, which had the COI sequence recorded only from China Sea, was found in the middle of the NJ tree nearby Hap_07 and showed a close relationship with Hap_07. This indicates that Chinese red spotted grouper is also maternally related to other populations in East Asia. Consequently, East Asian red spotted grouper populations are maternally related, as well as sharing the same evolutionary history, and are still affected by the East Asian ocean current (Kuroshio). These findings help to explain the genetic structure and phylogenetic relationship of red spotted grouper and also contribute to research on artificial breeding and industrialization.

Re-examining the relationship between invasive lionfish and native grouper in the Caribbean.

Biotic resistance is the idea that native species negatively affect the invasion success of introduced species, but whether this can occur at large spatial scales is poorly understood. Here we re-evaluated the hypothesis that native large-bodied grouper and other predators are controlling the abundance of exotic lionfish (Pterois volitans/miles) on Caribbean coral reefs. We assessed the relationship between the biomass of lionfish and native predators at 71 reefs in three biogeographic regions while taking into consideration several cofactors that may affect fish abundance, including among others, proxies for fishing pressure and habitat structural complexity. Our results indicate that the abundance of lionfish, large-bodied grouper and other predators were not negatively related. Lionfish abundance was instead controlled by several physical site characteristics, and possibly by culling. Taken together, our results suggest that managers cannot rely on current native grouper populations to control the lionfish invasion.

Single nucleotide polymorphisms in the leptin-a gene and associations with growth traits in the orange-spotted grouper (Epinephelus coioides).

Leptin is a multifunctional protein involved in processes such as body weight regulation, energy expenditure, fat metabolism, food intake, and appetite regulation. Duplicate leptin genes, leptin-a and leptin-b, were previously detected in the orange-spotted grouper. In this study, we cloned the full-length open reading frame (ORF) of the leptin-a gene in the orange-spotted grouper, searched for polymorphisms, and performed association analyses between these polymorphisms and seven growth traits. Six polymorphisms, consisting of 2 SNPs in intron 1 (c.182T > G, c.183G > T) and 4 SNPs in exon 2 (c.339C > G, c.345C > T, c.447G > A, c.531C > T), were identified and genotyped in 200 individuals. The c.182T > G and c.183G > T polymorphisms showed complete linkage and were analyzed together. Association analyses revealed that the c.182 + 183TG > GT polymorphism was significantly associated with body weight (BWT) and body width (BWH), with the AB (TG/GT) genotype showing positive effects on growth traits. Additionally, the SNP c.447G > A was significantly associated with BWT, BWH, overall length (OL), trunk width (TW), and head length (HL), with the GA genotype displaying positive effects on growth traits. The c.531C > T SNP showed a close association between the TT genotype and decreased growth. Our results demonstrate that several polymorphisms in the leptin-a gene are associated with growth traits and can be used for marker-assisted selection (MAS) in orange-spotted grouper populations.

Are the last remaining Nassau grouper Epinephelus striatus fisheries sustainable? Status quo in the Bahamas

Nassau grouper Epinephelus striatus is an important species recreationally, commer- cially, and for subsistence in the Bahamas. Within most of the species' range, over-exploitation has led to large declines in abundance and to disappearance of spawning aggregations. Nassau grouper is classified as 'Endangered' on the IUCN Red List of Threatened Species. The popula- tion(s) in the Bahamas is/are considered to be among the few remaining major Nassau grouper populations globally. However, the recent declining trend in the number of fish landed raises con- cerns about the sustainability of the Bahamas' population(s). In this study, we provide an appraisal of the current status of the fisheries and explore the potential effects of different fishery and con- servation management scenarios on the Nassau grouper population and the fisheries. The study uses existing biological and fishery data together with fishers' knowledge on fisheries collated from an interview survey. The results suggest that the population is now fully- to over-exploited and under decline, although this needs to be validated when more fishery and population data have been collected and analyzed. A precautionary approach to managing the Bahamas' Nassau grouper is to maintain spawning aggregation closures, and to improve the monitoring, control, and surveillance to address poaching. Also, fishing mortality rates should be reduced to below the 1998-2001 level during non-spawning aggregation periods. These measures will increase spawn- ing potential and maximize the long-term economic benefits of the fisheries. Other potential threats to the Nassau grouper population, such as the invasion of lionfish, increased use of com- pressors, and the taking of immature fish, should be monitored and assessed.

Reproductive Biology of the Tiger Grouper in the Southern Gulf of Mexico

AbstractDespite its commercial importance and high vulnerability to fishing impact, little is known about the reproductive biology of the Tiger Grouper Mycteroperca tigris, an aggregative spawner. We studied the key reproductive parameters of this species in the southern Gulf of Mexico, where the grouper fishery is generally in decline. The smallest mature female measured 31.4 cm FL, and length at which maturity was attained in 50% of females (L50) was 34.2 cm FL. Tiger Grouper are protogynous hermaphrodites, and the estimated length at which 50% of females had changed sex was 51.9 cm FL. Spawning season lasted from February to June, with a spawning peak observed in April. Most of the actively spawning females were collected 7–14 d after the full moon in April and May. Females exhibited continuous, asynchronous oocyte development and batch release of mature oocytes. During April–June, estimated spawning interval varied monthly from 1.8 to 4.3 d (mean = 2 d). Due to the species’ indeterminate fecundity, we estimated batch fecundity, which ranged from 84,119 to 1,032,578 oocytes (mean ± SE = 417,102 ± 34,826 oocytes). Conservation status of the Tiger Grouper in its distribution area is currently unclear. Based on the observed maximum sizes for both sexes and the size of sexual transition, the southern Gulf of Mexico Tiger Grouper population may be healthier than some Caribbean Sea populations. Current and potential measures for regulating this fishery resource in the southern Gulf of Mexico are discussed.

Phylogeography and Genetic Diversity of Humpback Grouper Cromileptes altivelis based on Cytochrome C Oxidase I

Humpback grouper is one of the most popular fish group in the international live trade in Asia-Pacific regions. The price for one kilogramlive of humpback grouper, especially in Spermonde Archipelago South of Sulawesi, is range from 350.000-400.000 IDR, whereas in theretail level in Hong Kong the price was about 92 US$. This condition leads to the reduction of nature population due to overexploitation.Population decreasing due to overexploitation may cause loss of genetic diversity within population and lead to reduce of potentialadaptive, population resistance, and productivity. Therefore, it is important to do some efforts to avoid adverse effect of overexploitationon humpback grouper population in Indonesia. One of the valuable efforts is providing genetic information such as phylogeography andgenetic diversity of humpback grouper Cromileptes altivelis. Analysis was based on 618 base pairs fragment of cytochrome c oxidase I genefrom 36 individuals (sequences) of Cromileptes altivelis collected at four different sites (e.g. Pulau Seribu, Jepara, Situbondo and SpermondeArchipelago). The results showed that humpback grouper population has a high haplotype and nucleotide diversity. However, high geneticdiversity and polymorphisms could not reveal population fragmentation (Φ stt = 0.000). It is suggested that high gene flow rather thanpopulation sub structuring was occurred. High level genetic diversity and polymorphisms are vital related to adaptive potential toenvironmental alteration.

Should the Critically Endangered Goliath grouperEpinephelus itajarabe culled in Florida?

AbstractThe Goliath grouperEpinephelus itajarahas been protected in the USA since 1990. In Florida commercial and recreational fishers consider the species a top predator of fish and lobster and advocate culling the grouper population as a solution to recover declining stocks. I examined the scientific evidence for and against culling the Goliath grouper, using commercial landing data from the National Marine Fisheries Service and the Florida Fish and Wildlife Conservation Commission (1950–2010), fisheries-independent diver-based surveys from the REEF Environmental Education Foundation (1993–2007), and published dietary and morphological studies. An analysis of the commercial extinction of the Goliath grouper in Florida indicates that its recovering population is not the cause of declining fish and lobster stocks. The recovering Goliath grouper population could provide ecological and socio-economic benefits: as top-down control on other lobster predators, in ecotourism, and as potential biocontrol of the invasive Indo-Pacific red lionfishPterois volitanson Atlantic reefs.

Gag grouper, marine reserves, and density-dependent sex change in the Gulf of Mexico

The use of marine reserves for fishery management remains a controversial tool despite evidence of their success. In the Gulf of Mexico (GOM), two marine reserves were put in place in order to protect spawning aggregations of gag grouper, which has experienced a steep decline in the male to female sex ratio since the 1970s. Reserve success is ultimately a function of the total amount of spawning aggregations protected, and fisher response to reserve implementation may have significant influence on the ultimate effectiveness of the reserves. We modeled the GOM gag grouper population under a range of potential reserve sizes and fisher responses. In general, larger reserves resulted in higher adult populations and sex ratio. Fisher response to reserves also had a large impact on reserve success. When we included density-dependent sex change in the model, the results showed a reduction in the sex ratio under high fishing pressure when compared to model simulations when sex change was fixed. While our model suggests that the reserves currently in place should result in a small increase in adult sex ratio given the current level of fishing mortality, such benefits might not be achieved in practice given possible future changes in transition rates or fisher behavior.

Age, growth, and reproductive aspects of the dusky grouper Mycteroperca marginata (Actinopterygii: Epinephelidae) in a man-made rocky habitat in southern Brazil

The dusky grouper, Mycteroperca marginata, is an important commercial marine fish that is currently considered an endangered species worldwide and listed as overexploited in Brazil. Although its reproductive biology has been studied elsewhere, no information is available for populations in its southernmost distribution limit on the Brazilian coast. The present work investigates age structure, growth and reproduction of individuals inhabiting a pair of rocky jetties, about 4.5 km long each, located in the mouth of Patos Lagoon in the municipality of Rio Grande, in the southwestern Atlantic Ocean. A total of 130 individuals obtained between February 2007 and May 2009 were analyzed, with total length ranging from 260 to 800 mm. The growth coefficient found in the present study (K: 0.069) was lower than values reported for dusky grouper populations from the Mediterranean Sea (0.087) and southeast Africa (0.09). This difference could be related to higher average water temperatures in these regions compared to the current study site or due to poorer habitat quality in terms of the shelters available for dusky grouper individuals to establish their territories. Microscopic ovarian analyses of individuals during three years of sampling revealed only the occurrence of immature and resting females. The absence of ripe or post-spawning individuals, associated with low GSI values (<0.2) over the studied months, indicates that the dusky grouper did not use this man-made rocky substrate as a spawning site. The current L50 estimate of 451.3 mm indicates that most individuals captured in this area are immature. Such fishing pressure on immature specimens, associated with its slow growth rates and complex reproductive characteristics, threatens sustainability of the current dusky grouper fishery at the study site.

Pattern of Recovery of the Goliath Grouper <I>Epinephelus itajara</I> Population in the Southeastern US

In the present study, we evaluate the past and current distribution and abundance of the atlantic goliath grouper, Epinephelus itajara (Lichtenstein, 1822), in coastal waters of the southeastern United States. The study is based on quantitative surveys conducted by us (n = 190) and the Florida Fish and Wildlife Conservation Commission's Artificial Reef Program (n = 505), coupled with semi-quantitative data submitted by volunteer divers to the Reef Environmental Education Foundation (n = 27,542) over the past 15+ yrs. The vast majority of the goliath grouper population is restricted to Florida waters. We found that the population of goliath grouper, after dramatic fishery-induced declines in the 1970s and 1980s, and eventual fishery closure in the 1990s, increased off southwest Florida in the mid-1990s, directly offshore of the high-quality mangrove nursery of the Ten Thousand Islands. It then expanded north and south, eventually increasing off Florida's central east coast. Tagged fish, regardless of life stage, showed strong site fidelity to home sites: juveniles (2963 tagged, 32.6% recaptured) to mangrove nursery sites and adults (2110 tagged, 7.6% recaptured) to offshore reefs. All long-distance movements appeared to be in response to approaching maturity, with juveniles emigrating from mangroves to take up residence on offshore reefs, to seasonal spawning activity, with adults moving from home sites to aggregation sites, or to apparent feeding sites in inlets. Understanding these patterns of population recovery and movement is fundamental to devising appropriate management policies.

Genetic diversity and differentiation of the orange-spotted grouper (Epinephelus coioides) between and within cultured stocks and wild populations inferred from microsatellite DNA analysis.

In the present study, we employed microsatellite DNA markers to analyze the genetic diversity and differentiation between and within cultured stocks and wild populations of the orange-spotted grouper originating from the South China Sea and Southeast Asia. Compared to wild populations, genetic changes including reduced genetic diversity and significant differentiation have taken place in cultured grouper stocks, as shown by allele richness and heterozygosity studies, pairwise Fst, structure, molecular variance analysis, as well as multidimensional scaling analysis. Although two geographically adjacent orange-spotted grouper populations in China showed negligible genetic divergence, significant population differentiation was observed in wild grouper populations distributed in a wide geographical area from China, through Malaysia to Indonesia. However, the Mantel test rejected the isolation-by-distance model of genetic structure, which indicated the genetic differentiation among the populations could result from the co-effects of various factors, such as historical dispersal, local environment, ocean currents, river flows and island blocks. Our results demonstrated that microsatellite markers could be suitable not only for genetic monitoring cultured stocks but also for revealing the population structuring of wild orange-spotted grouper populations. Meanwhile, our study provided important information for breeding programs, management of cultured stocks and conservation of wild populations of the orange-spotted grouper.

Diet and feeding strategy of the dusky grouper Mycteroperca marginata (Actinopterygii: Epinephelidae) in a man-made rocky habitat in southern Brazil

The dusky grouper (Mycteroperca marginata) is a marine species usually associated with rocky bottoms and reefs. The present work investigated the diet and feeding strategy of a dusky grouper population inhabiting a 4.5 km long pair of rocky jetties located in the mouth of Patos Lagoon estuary. No prior research has been conducted in such man-made habitat and the current study provides a basis for comparative studies on the diet of the dusky grouper populations inhabiting natural vs. man-made rocky habitats. Similarly with previous studies on natural substrates, crabs and fishes were the main food categories consumed (%IRI = 85.1 and %IRI = 12.6, respectively), whereas shrimps and mollusks had lower importance in the diet (%IRI = 1.9 and 0.4, respectively). As previously reported for dusky grouper populations inhabiting reefs and rocky bottoms, the present work revealed conspicuous size related dietary shifts. Blue crabs and fishes become increasingly important food items in the diet of larger individuals (> 500 mm, TL). Finally, it was found that the studied dusky population has a generalist feeding strategy with a high between-individual variation in prey consumption. Such strategy remained similar across the size increment of the species. Our findings suggest that man-made rocky substrates provide suitable feeding grounds for the dusky grouper in southern Brazil and could be used as an additional tool in the conservation efforts of this endangered species.

Individual Based Model for Grouper Populations

Dusky groupers (Epinephelus marginatus) are characterized by a complex sex allocation strategies and overexploitation of bigger individuals. We developed an individual based model to investigate the long-term effects of density dependence on grouper population dynamics and to analyze the variabilities of extinction probabilities as a result of interacting mortalities at different life stages. We conduct several simulations with different forms of sex allocation functions and different combinations of mortality rates. The model was parametrized using data on dusky grouper populations from the literature. The most important insights produced by this simulation study are that density dependence of sex allocation is an evolutionarily stable strategy, increases the population biomass, mitigates the effect of the removal of large male and indicates a need for protection of females and flexible stages.

Mathematical Modeling Describing the Effect of Fishing and Dispersion on Hermaphrodite Population Dynamics

In order to study the impact of fishing on a grouper population, we propose in this paper to model the dynamics of a grouper population in a fishing territory by using structured models. For that purpose, we have integrated the natural population growth, the fishing, the competition for shelter and the dispersion. The dispersion was considered as a consequence of the competition. First we prove, that the grouper stocks may be less sensitive to the removal of large male individuals if female population are totally protected. Second, we show that fishing does not disturb the demographic structure of the population. Finally, we prove that female selective fisheries have the potential of drastically reduce reproductive rates. We also prove that male fishing decreases competition and then increases the total population number.

Effects of an artisanal fishery on non-spawning grouper populations

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 392:253-262 (2009) - DOI: https://doi.org/10.3354/meps08236 Effects of an artisanal fishery on non-spawning grouper populations Philip P. Molloy1,*, John D. Reynolds1, Matthew J. G. Gage2, Isabelle M. Côté1 1Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada 2Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK *Email: pmolloy@sfu.ca ABSTRACT: Many populations of groupers (Teleostei: Serranidae) are overfished, partly because most species form spawning aggregations that are temporally and spatially predictable and therefore easily targeted by fisheries. However, most grouper fisheries operate year-round, thus there can also be high mortality during non-spawning periods. We investigated the impact of fishing around Anguilla, British West Indies, on a commercially important grouper, the red hind Epinephelus guttatus, during the non-breeding season. We combined information on the spatial intensity of the fishery with underwater surveys of groupers to test for associations between fishing intensity and fish size and density across 19 sites. Red hind density was unrelated to fishing intensity but red hinds were larger in areas that were targeted more intensively by fishers. While these results might be taken to suggest that fishing has no negative impacts on red hind demographics, we present evidence from fish markets that fishing intensity on this species during the non-spawning season is high. A variety of mechanisms may mask site-specific negative impacts on density and size of red hinds. In particular, fishers can easily move among sites to track grouper abundance and body size, thereby making it difficult to detect impacts on red hinds during the non-spawning season. KEY WORDS: Caribbean · Coral reef · Grouper · Overexploitation · Serranid · Spawning aggregation · Subsistence fishery Full text in pdf format PreviousNextCite this article as: Molloy PP, Reynolds JD, Gage MJG, Côté IM (2009) Effects of an artisanal fishery on non-spawning grouper populations. Mar Ecol Prog Ser 392:253-262. https://doi.org/10.3354/meps08236 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 392. Online publication date: October 19, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Historical declines of goliath grouper populations in South Florida, USA

Historical data are important in fisheries management and conservation, particularly for species which suffered significant population declines prior to the collection of ecological data. The globally endangered goliath grouper Epinephelus itajara was fished intensively long before data on population size were first collected. Historical population estimates have significant management implications, as the estimated time to full recovery depends on the size of the baseline population before depletion. Evidence used previously suggests that goliath grouper populations in Florida were reduced by as much as 95% relative to estimated baseline levels at the time of protection in 1990 and have since recovered to more than 30% of these values. However, actual historic abundances are not well known because few early data exist. I present 2 new data sets: (1) historical photographs of ‘trophy fish’ and (2) newspaper articles from the Florida Keys. I analyzed goliath grouper in photos taken of fish caught on Key West charter boats from 1956 to 1985 to assess changes in abundance before the fishery was closed in 1990. The average number of individuals displayed per trip decreased before 1960 and was reduced by 86% before 1979. Further evidence of declines is found in newspaper accounts of landings (1923 to 1977), which show decreases in the maximum individual fish size caught and the proportion of large grouper caught from land vs. offshore before 1950. These results demonstrate population declines over longer time scales than are currently considered and suggest that recent increases do not represent significant recovery compared to population abundances before depletion.

How many species of goliath grouper are there? Cryptic genetic divergence in a threatened marine fish and the resurrection of a geopolitical species

The goliath grouper Epinephelus itajara (Epinephelidae) is an exceptionally large marine fish that inhabits sub-tropical and tropical waters of the Americas and western Africa. Due to a lack of readily observable morphological variation in specimens across its range, the goliath grouper has been regarded as a single species. We tested the hypothesis that Pacific and West Atlantic populations constitute a single species by analyzing nuclear and mitochondrial DNA sequence data. We found numerous fixed genetic differences for mitochondrial loci between Pacific and West Atlantic goliath grouper (genetic distance D ≈ 3.5% at 16S and D ≈ 6% at cytochrome b; ϕst = 0.98 (p < 0.001) for 16S and ϕst = 0.98 (p < 0.001) for cytochrome b). The nuclear S7 intron showed 3 fixed nucleotide differences between Pacific and West Atlantic populations. Within the West Atlantic, we found few absolute genetic differences (D < 0.01 at 16S and D < 0.02 at cytochrome b), but statis- tically significant population structure based on haplotype frequency data (ϕst = 0.04 (p = 0.05) at 16S; ϕst = 0.14 (p < 0.001) at cytochrome b). These data indicate that (1) goliath grouper in the West Atlantic are subdivided into discrete populations, (2) goliath grouper populations in the Pacific and western Atlantic represent 2 (or more) distinct species, and (3) these distinct populations/species require separate management and conservation strategies. We resurrect the species Epinephelus quinquefasciatus Bocourt 1868 for Pacific goliath grouper.

Acoustic telemetry survey of the dusky grouper ( Epinephelus marginatus) in the Marine Reserve of Cerbère-Banyuls: informations on the territoriality of this emblematic species

The Marine Reserve of Cerbère-Banyuls represents a refuge for dusky grouper populations ( Epinephelus marginatus). Density survey and observation of the reproductive behavior of this species have been conducted there for the last 30 years. However, information on the behavior or habitat utilization for this species during winter time is limited. We conducted acoustic telemetry surveys from September 2005 to June 2006 in the Marine Reserve of Cerbère-Banyuls for a dusky grouper population. Six groupers were tagged and followed within the integral reserve and in the adjacent partial reserve. The results from the tracking of these individuals indicated that the largest dusky groupers are sedentary fishes with a high degree of site fidelity and a high sensitivity to variations of environmental conditions such as storms. This together with the life history characteristics of this species encourages the conservation and the protection of essential habitats of this species. Acoustic tracking coupled to the use of a fixed Kernel can be proposed to follow fish populations. To cite this article: J. Pastor et al., C. R. Biologies 332 (2009).