Grouper Populations Research Articles

Dusky grouper massive die-off in a Mediterranean marine reserve

The dusky grouper Epinephelus marginatus (Lowe, 1834) is a key predator in shallow Mediterranean rocky habitats. Due to fishing pressure and slow population dynamics, dusky grouper populations are declining across their distribution range. Here we document a massive die-off of E. marginatus in the Columbretes Islands Marine Reserve (NW Mediterranean Sea) during the summer and early autumn of 2023. The mortality event was triggered by a Betanodavirus infection. Genetic characterization of isolates from the affected fish confirmed that they belong to the RGNNV genotype. Our findings indicate that such disease outbreaks can be particularly severe in areas with dense dusky grouper populations, potentially undermining the historical conservation effectiveness of marine protected areas. Although our results do not determine whether the infection originated from wild or farmed fish, it is essential to implement monitoring and early detection systems for Betanodavirus infections in both wild and farmed fish to prevent cross-infections.

Broken expectations: Population decline of a key grouper species within a 30-year-old no-take MPA in the Southwestern Atlantic

Understanding the impacts of human actions on marine species and developing mitigation strategies are crucial conservation challenges. Many fish species, especially marine top predators, are already highly depleted and rely on population monitoring and conservation strategies for their maintenance. In this context, Marine Protected Areas can help recover target species and provide crucial information about population trends when human activities are restricted or managed. Here, we used the longest and most complete temporal series of reef fish data in the Southwestern Atlantic, comprising 16 years of underwater visual census sampling. We evaluated temporal trends in the density and biomass of the dusky grouper (Epinephelus marginatus), both inside and outside a no-take and no-entry Marine Reserve. Our findings reveal a consistent decline in density and biomass inside and outside the MPA over time, reaching alarmingly low densities and experiencing a steeper biomass decline in the last five years. Our results contradict global expectations of positive population recovery trends within MPAs. We highlight the adverse impacts of human activities on the dusky grouper population, including illegal fishing and habitat degradation. Additionally, we address the limited understanding of species' life stages, underscoring that their occurrence outside protected boundaries may render the entire population vulnerable to human pressures. Thus, to guarantee population recovery, stakeholders and researchers must take immediate action to increase knowledge of all life stages and improve ongoing strategies.

KARAKTERISTIK IKAN KERAPU DI PASAR ARUMBAI AMBON

Arumbai Market in Ambon City, Maluku Province, is a central hub for the trade of fishery products, particularly groupers. This study aims to describe the origin of grouper catches and to identify the species and sizes of groupers marketed at Arumbai Market. Groupers, which belong to the family Serranidae, are the primary predators in coral reef ecosystems. Fish identification was conducted based on Allen's guide and verified through FishBase. The study was conducted from December 2022 to February 2023 using a survey method through direct observation and interviews. Data were analyzed descriptively and presented in tables and graphs. The results showed that groupers at Arumbai Market come from four main locations: Manipa (34.47%), Liang (26.81%), Latuhalat (24.26%), and Pulau Tiga (14.47%). Eight dominant species of groupers in this market are Variola albimarginata (44.64%), Cephalopholis miniata (20.60%), Epinephelus fasciatus (12.45%), Epinephelus ongus (6.44%), Cephalopholis urodeta (6.44%), Cephalopholis sonnerati (5.58%), Epinephelus areolatus (3.00%), and Epinephelus fuscoguttatus (0.86%). Grouper sizes vary, with Cephalopholis miniata having a maximum size of 27.1 cm and a minimum size of 19.9 cm. This study provides essential information on the origin of catches, species dominance, and sizes of groupers marketed, which can serve as a basis for better fishery management. These findings indicate a significant potential for grouper trade in the region and highlight the importance of sustainable management to preserve the continuity of coral reef ecosystems and grouper populations.

Diving into archival data: The hidden decline of the giant grouper (Epinephelus lanceolatus) in Queensland, Australia

AbstractThe giant grouper (Epinephelus lanceolatus) is the largest reef fish in the Indo‐Pacific (~2.5 m TL, >400 kg), and it is highly susceptible to overfishing. Despite regional protections and documented population declines, the species is listed by IUCN as Data Deficient due to minimal long‐term population data and a paucity of life history information. This study used historical fishing records derived from newspaper articles, fishing magazines, grey literature and naturalists' descriptions to collate life history information and reconstruct giant grouper population trends from 1854 to 1958 in Queensland, Australia. Historical recreational catch trends of four biologically distinct grouper size classes demonstrated that over 92 years, fishing disproportionately affected two size classes: immature (fish below reproductive size) and mature individuals. Changes in the probability of capturing a grouper within a recreational fishery were examined as a proxy of relative abundance. The probability of catching a giant grouper within a popular recreational fishery significantly declined from 81% in 1860 to 2% in 1958. Further analysis based on a non‐probabilistic method of giant grouper sighting records showed fluctuations in the giant grouper population trajectory, from a steady decline during the early 20th century to an increase during WWII (1939–1945) followed by a reduction in the last half of the 20th century. This study highlights the importance of archival sources to uncover population trends of rare species by combining quantitative assessments and biological inferences to determine the timing and occurrence of population declines and recoveries and inform how vulnerable fish species respond to the cumulative effects of fishing over time.

Comparative Analysis of the Distribution and Composition of Grouper Fish (Family Serranidae) in the Coral Reef Ecosystems of Batanta and Salawati Islands, Raja Ampat

The Coral Reef Ecosystems of Batanta and Salawati Islands, Raja Ampat is a critical habitat for grouper species (Family Serranidae), which play essential roles in coral reef ecosystems. This study assessed the species composition, abundance, and biomass of groupers across 12 sampling sites in the region. Using the Underwater Visual Census (UVC) method, we identified 14 grouper species, with Plectropomus areolatus classified as vulnerable by the IUCN. Our results revealed an average grouper abundance 17.33 ind/350m2 for Batanta and 18.33 ind/350m2 for Salawati. An average biomass the mean biomass 4288.16 gr/350m2 for Batanta and 1881.10 gr/350m2 for Salawati, indicating substantial biomass within the area. Statistical analyses, including the Kruskal-Wallis test and t- tests reveal no significant difference in abundance between the two locations, as indicated by the non-significant p-value (p = 0.87). Correlation analysis demonstrated a very strong positive relationship between grouper abundance and biomass, suggesting that the Anthropogenic activities have not yet significantly impacted the grouper populations in Salawati and Batanta. The study emphasizes the importance of habitat protection and sustainable fisheries management to support grouper populations. Additionally, ongoing monitoring and adaptive management strategies are necessary to ensure the long-term health of grouper populations and the coral reef ecosystems they inhabit.

Controversial opening of a limited fishery for Atlantic Goliath Grouper in the United States: Implications for population recovery

Laws protecting the Atlantic Goliath Grouper Epinephelus itajara from fishing in federal and state waters of the United States (US) occurred in 1990 after the species was identified as being severely overfished. Population increases that occurred during the first 20 years of the closure were followed by a decline in the 10 years thereafter. Despite the National Oceanic and Atmospheric Administration’s call to retain full protection for this species in federal waters, the Florida Fish and Wildlife Conservation Commission (FWC) decided to open a limited fishery in state waters for juveniles. Here, we review the literature demonstrating the initial recovery of Goliath Grouper in the U.S., the limits of that recovery, and the ensuing factors that precipitated its subsequent decline; we discuss the risks associated with management decisions that ignore the best available scientific information; and we compare management differences and difficulties among nations within the Atlantic Goliath Grouper’s global range. The major findings are that Goliath Grouper populations have not fully recovered and that FWC has not sought to conserve and protect them. Resolving these problems will require the Governor of the State of Florida to appoint Commissioners that represent a range of stakeholders with expertise in ecology, conservation, and management beyond that provided by the FWC agency; to better train appointees lacking in those areas; and to choose candidates who embrace use of the best available science in making critical decisions that affect Florida ecosystems, native species, and Florida residents.

Are the Coastal Waters of French Guiana a Source or Sink Habitat for Atlantic Goliath Grouper Epinephelus itajara?

The coastal waters of French Guiana are amongst the most turbid and nutrient rich in the world, and as such, they favour the settlement and early development of several species of marine fish. Recent work has revealed a high abundance of Atlantic Goliath Grouper (Epinephelus itajara) in these waters, yet little is known about this species’ reproductive biology, which this study aims to complement. During the period from 2010 to 2013, we surveyed Goliath Grouper at three rocky sites along the French Guiana coast and examined 602 individuals for evidence of maturation. Satellite tags were deployed on five individuals and an acoustic survey was conducted to identify potential spawning movements and activity. We found no evidence of sexually active individuals or local spawning aggregations. Most individuals showed high site fidelity, but one fish was located 1150 km away, near Trinidad and Tobago. We discuss these findings in the context of the wider literature and postulate that Goliath Grouper inhabiting French Guiana reefs originate from spawning sites in northern Brazil and disperse to westerly reefs with the onset of maturity. We propose that the Goliath Grouper populations of South America and Caribbean are linked, and that management of Brazilian source populations could have wide-reaching impacts on Goliath Grouper stocks.

Residency and Fine-scale Habitat Use of Juvenile Goliath Grouper (Epinephelus Itajara) in a Mangrove Nursery

The Atlantic goliath grouper (Epinephelus itajara) is the largest grouper species in the Atlantic and exhibits high site fidelity and limited range of movement. By 1990, the goliath grouper population in US waters had declined approximately 95% relative to unfished levels, leading to a harvest ban in 1990. Since then, the south Florida population has grown but the magnitude of recovery remains unknown due to uncertainties about life history characteristics. However, despite these unknowns, the state of Florida approved a limited recreational harvest of goliath grouper. In 2021, fine-scale habitat use of three juvenile goliath grouper was investigated using acoustic telemetry and a positioning solver. All three individuals exhibited high site fidelity as well as a diel habitat use pattern, utilizing seagrass habitat during the night and mangrove habitat during the day. Fine-scale acoustic telemetry provides insight into not only habitat use, but broader habitat preferences as well. This study illustrates the need to consider deep seagrass-dominated channels lined with red mangroves when protecting juvenile goliath grouper populations within Florida Bay, especially as the population is opened to harvest.

Species Composition and Growth Pattern of a Multi-Species Grouper in Kwandang Bay, Sulawesi Sea, Indonesia

Highlight Research There are 26 species identified to be originated from the bay, which the highest diversity in Indonesia Six species found in Kwandang Bay is showing trends of decreasing populations and two species vulnerable based on IUCN conservation list Growth model and Fulton condition factor determined for 14 species indicates that they live in a good state of well beings in the bay The models and condition factors also reflect the adequate food resources required for grouper growth which makes Kwandang Bay as a good habitat for groupers Abstract Grouper fishery has been the source of income for 3,700 fishermen in Kwandang Bay. Since 2017, grouper populations in Kwandang have been depleting due to the absence of management. This research aimed to analyze species composition, length-weight relationship, and condition factor of the groupers. Samples were collected from fishers who caught the fish using traps, speargun, and handline. Samples were identified through a method by Heemstra and Randall, while the length-weight relationship was estimated using log-linear regression and t-test. The number of specimens identified during January - December 2021 was 1,571 individuals. Research showed that those samples consisted of 26 species under eight genera. Six species found in Kwandang Bay were showing trends of decreasing populations and two species were vulnerable based on the IUCN conservation list. Length-weight relationship analysis of 14 grouper species resulted in b value ranging from 1.6359 to 3.4417 and R2 ranges from 0.7718 to 0.9858. A significant test at a 95% confident interval showed that 14 species had an isometric growth pattern. Fulton condition factors show that Kwandang Bay is an essential habitat for groupers, and the bay can support the fish growth due to the adequate food availability.

Seasonal temperatures in South Eleuthera, The Bahamas, have considerable impacts on the cardiorespiratory function and swimming performance of Nassau grouper (Epinephelus striatus)

Abstract Surprisingly, the impacts of environmental changes on the physiology of tropical/subtropical marine fishes have received limited attention. Given that (i) temperature is considered to be a key factor controlling the biology of fishes; (ii) no published data are available on the swimming performance, metabolic capacity or cardiac function of any of the ~165 grouper species worldwide; and (iii) the Nassau grouper is an endangered species of great ecological and socioeconomic significance in The Bahamas, we investigated how current summer/early fall (30°C) and winter (22°C) temperatures in South Eleuthera affected the aerobic metabolism and heart function of wild Nassau grouper when swum to exhaustion (i.e. to their critical swimming speed, Ucrit). The Nassau grouper had a very low Ucrit at 30°C (i.e. <1 body lengths s−1), and a 30% lower swimming performance during the winter (at 22°C), and this was that was indicative of a reduced absolute aerobic scope (~185 vs. 290 mg O2 kg−1 h−1) and values of maximum heart rate ($f$HMax) and scope for $f$H that were only one-half of that achieved at 30°C (~60 vs. 120 and 29 vs. 61 beats min−1, respectively). Overall, these data reveal that the Nassau grouper’s aerobic and swimming capacity are well below values reported for other tropical/subtropical fishes and suggest that, despite a compensatory (~30–40%) increase in stroke volume, constraints on $f$H near this species’ lower thermal limit negatively affect its cardiac output and swimming performance. These findings have considerable ecological implications as Bahamian grouper populations migrate over long distances to spawn during the winter months, and given the predicted increase in temperature variability with climate change.

Catch of the day: Abundance and size data of groupers (Epinephelidae) and combers (Serranidae) from Middle to Late Holocene Levantine archaeological contexts

Groupers (Epinephelidae) are ecologically, commercially, and culturally important carnivorous fishes found throughout the world’s tropical, subtropical, and temperate coastal marine waters. Due to various life history traits (e.g., late maturity, sequential hermaphroditism) and behavior (e.g., sedentary, small home ranges) groupers are susceptible to overfishing, including small-scale and recreational fishing (especially spearfishing), and their populations are declining worldwide. The eastern Mediterranean coast, home to some of the world’s longest continuously occupied urban settlements, hosts important but declining grouper populations. This paper investigates how grouper and comber (fishes in the Serranidae family with similar ecology and osteomorphology, but smaller in size) abundance and catch size changed in the eastern Mediterranean from the Middle to Late Holocene, coinciding with early coastal urbanization, by estimating their relative frequency and reconstructing their size. Size reconstructions have been done from a large sample of bones (Number of Identified Specimens = 1851) recovered from Kinet Höyük in Turkey, and Tell Fadous-Kfarabida and Tell el-Burak in Lebanon, habitation sites along the Levantine coast. Our results imply that groupers in the past reached >100 cm more often than is observed today in areas open to commercial fishing. Furthermore, the apparent lack of large groupers by the Hellenistic Period at Kinet Höyük suggests fishing efforts were intense enough to have either had an appreciable effect on the size structure of local grouper populations or brought about a behavioral change to the fishes of moving to deeper waters.

Incidental fishing of Epinephelus itajara (Lichtenstein, 1822): the vulnerability of a critically endangered species of the Brazilian coast

Epinephelus itajara, popularly known as grouper, has a wide distribution and is considered the largest fish in the Atlantic Ocean. Behavioral characteristics allied to overfishing and degradation of marine habitats caused declines in E. itajara populations throughout the entire geographic distribution area. The goliath grouper is currently ranked on the IUCN RedList as Vulnerable in Global Status and Critically Endangered in the Gulf of Mexico. In Brazil, even with a fishing moratorium that has protected it since 2002, the species is categorized as critically endangered in the Red Book of the Instituto Chico Mendes de Conservação da Biodiversidade. Taking into account these factors and the information gap on the goliath grouper, this study addresses an account of an occasional “post mortem” encounter with a specimen on the edge of Pajuçara beach, Maceió - Alagoas. It was an adult individual, whose size was estimated at 1.6 m and 70 kg of body mass. This study also presents discussions about the conservation status of the species and the efficiency in the management of marine protected areas, revealing that even with many marine protection areas, incidental captures and port records are still recurrent on the Brazilian coast. This record highlights the need to reinforce inspections, in addition to suggesting that the management of these areas be more efficient, ensuring the reestablishment of grouper populations in the region.

Filling gaps in the knowledge of grouper, especially Comb grouper (Mycteroperca acutirostris) (2013-2020) (Copacabana fishery, Rio de Janeiro, Brazil)

There are gaps in our knowledge of important fish consumed by people in tropical countries. Small-scale fisheries are difficult to regulate, especially in countries with no species monitoring. At Copacabana (Rio de Janeiro), we observed 490 individuals of badejo (Comb grouper) (Mycteropeca acutirostris in 2013-2014 and in 2018-2020. The average catch was 1.36 kg (n=466 individuals). A pattern of decreasing catches was observed for Comb grouper. Therefore, provided that the fishing gear and the number of fish have remained the same, the apparent decrease in Comb grouper needs to be further investigated. The results provide information about the major spawning season, around spring (September-December) with additional spawning during April. Genetic analyses in samples from 96 grouper obtained along the coast of Brazil were conducted. The Single Nucleotide Polymorphism (SNP) loci obtained for grouper species enabled us to determine the relative genetic proximity of M. acutirostris and Mycteroperca bonaci, information that can be useful for aquaculture and conservation. The objectives of this study were: a) to obtain data about the fishing activity (catch landings) of Comb groupers at Copacabana, Posto 6; b) to verify the reproductive period of Comb grouper, throughout the year, through the catches from the fishery; c) to develop a large numbers of SNP markers, which can be useful to studies about grouper populations (Mycteroperca and Epinephelus); and, d) to obtain data on the price of the Comb grouper. This study contributes data on the fishery and on the biology and ecology of groupers, and further contributes to conservation efforts.
 Keywords: comb grouper, fisheries, genetics, Mycteroperca.

A study of brown-marbled grouper (Epinephelus fuscoguttatus) population dynamics in Takabonerate National Park Waters, South Sulawesi, Indonesia

Abstract. Fatma, Mallawa A, Najamuddin, Zainuddin M, Fachrie R. 2021. A study of brown-marbled grouper (Epinephelus fuscoguttatus) population dynamics in Takabonerate National Park Waters, South Sulawesi, Indonesia. Biodiversitas 22: 4298-4307. Understanding aspects of the population dynamics of groupers such as the brown-marbled grouper can provide valuable insights into how to manage grouper stocks effectively. Conducted from February 2020 to February 2021 in Takabonerate National Park waters, Selayar Islands District, South Sulawesi, Indonesia, this study sought to elucidate the size structure and cohorts, population growth rate, total mortality rate, fishing mortality rate, natural mortality rate, exploitation rate and yield per recruit (Y/R) of the brown-marbled grouper. Grouper samples were caught using several fishing gears (i.e., hand line fishing, spearfishing, and trapping) with a total catch of 1042 specimens. The sampled specimens exhibited significant size structure and were classified into five age-specific cohorts. The growth rate coefficient was 0.46/year, with the brown-marbled grouper population tending to exhibit slow growth (K < 0.5/year). The estimated asymptotic length was 109.0 cm. The fishing mortality was higher than the natural mortality, with an exploitation rate of 0.65, indicating that brown-marbled groupers in the waters of Takabonerate National Park have been subjected to extensive and intensive fishing, as also indicated by an estimated Y/R lower than the optimum Y/R rate.

Biomass dynamic model for multiple data series: An improved approach for the management of the red grouper (Epinephelus morio) fishery of the Campeche Bank, Mexico

This study analyzed the current status of the population and stock assessment of the red grouper Epinephelus morio from the Campeche Bank, Yucatán, based on the Schaefer biomass dynamic model and considering the three fleets that operate in the study area. Thus, five indices of relative abundance were used, expressed as catch per unit effort (CPUE). The carrying capacity (K) of the red grouper population was 293,851 t, with an intrinsic growth rate (r) of 0.232. The study indicated that the greatest contribution to the adjustment of the model was due to the CPUE of the industrial Mexican fleet. The catchability values showed differences between the fractions of red grouper caught using trips and hooks. Estimates of maximum sustainable yield (MSY= 17,031 t) and biomass at MSY (BMSY= 146,929 t) indicated that the current catch and the biomass are below their reference points, denoting a marine resource that has been overharvested. Historical analysis of the biomass and harvest ratio for the red grouper estimated from the Kobe diagram showed that the red grouper fishery has transitioned from overfished-overharvested from 1984 to 2014 to overfished-underharvested in 2015. Because the E. morio stock is particularly low in abundance, catches must be drastically reduced to allow the stock to recover more quickly. Only low quotas (3,200–4,000 t) or an annual harvest rate of 6% will reach the BMSY in the long term, recognizing that, for both management strategies, the MSY will not be reached for at least 15 years.

Temporal variation of grouper diversity and distribution on the continental shelf of Sri Lanka: A revisit after four decades

Groupers (family Epinephelidae, subfamily Epinephelinae) are reef fishes of high value as food resources that generate export revenue to Sri Lanka. Yet, with less attention and poor resource management, grouper population dynamics remain understudied. This paper investigates the temporal variation of grouper species on the continental shelf of Sri Lanka in relation to seasonal, regional, and seafloor depth variables using data based on quantitative sampling of demersal fish conducted in 1978, 1979, 1980, and 2018 with a bottom trawl on the R/V Dr. Fridtjof Nansen, where the authors joined the 2018 survey. A total of 277 trawl samples were included in the analysis. The analysis of variance of all the grouper species found that the average density significantly declined from 0.89 t/NM2 (tonnes per square nautical mile) in 1979 to 0.28 t/NM2 in 2018. The contribution of groupers to the total catch (by weight) was also higher in 1979 (9.06 %) than in 2018 (1.28 %). The distribution patterns significantly differed among the six regions of the Sri Lankan shelf. In addition, seafloor depth was negatively correlated with grouper density. The results point to an urgent need for better management and conservation of the grouper resources.

Global population genetic structure of the sequential hermaphrodite, dusky grouper (Epinephelus marginatus)

Abstract The dusky grouper Epinephelus marginatus is a large epinephelid species that occurs in the eastern and south‐western Atlantic and western Indian Oceans. Late maturity, protogynous hermaphroditism, site fidelity, and overfishing have all contributed to its demographic decline. Connectivity and demography within a broad sampling of dusky grouper populations throughout its distribution were assessed. To do so, genetic variation at 11 polymorphic microsatellite loci and a partial sequence of the mitochondrial control region (mtCR) were evaluated. Two major mtCR lineages with a sequence divergence of 1.6% were found. The magnitude of genetic differentiation for mtCR among north and south Atlantic and Indian Ocean populations was high, with ΦST = 0.528. DEST and results of discriminant analysis of principal component revealed significant microsatellite genetic differentiation between all collection areas. Significant pairwise DEST showed moderate (0.084) to very great (0.603) differentiation. The effective population size was low for all localities, ranging between 25 (Azores Archipelago) and 311 (Rio Grande do Sul). The overall effective population size was estimated as 299 (confidence interval = 215–412), and there was no evidence of strong or recent bottleneck effects. Local and regional genetic structuring among dusky grouper populations is the consequence of the species' site fidelity, distribution across multiple oceanographic boundaries, and probably also of sequential hermaphroditism that contributes to the intensity of random genetic drift. The spatial pattern of genetic structuring of dusky groupers is such that fisheries management and conservation of population genetic integrity will have to be pursued at the local and regional scales.

Goliath grouper Epinephelus itajara oral history, use, and conservation status in the Mexican Caribbean and Campeche Bank

The Atlantic goliath grouperEpinephelus itajarais highly vulnerable to overfishing, yet little is known of its population status in Campeche Bank (southern Gulf of Mexico) and the Mexican Caribbean. By reviewing landings records, historical literature, and the local ecological knowledge of fishers, we documented historical practices, uses, and changes in the abundance and distribution of the goliath grouper in these regions. In both the Mexican Caribbean and Campeche Bank, goliath grouper populations were notably impacted by commercial fishing activities in the 1970s and 1980s. The catches during this period could only be sustained for a few years, after which the fishery collapsed. Our results from Campeche Bank indicate that populations persist in an area currently occupied by oil platforms. In the Mexican Caribbean, the extirpation of the goliath grouper may be close at hand, with local exceptions like that of Chetumal Bay. The results of our study indicate that the local goliath grouper populations are in critical danger of extinction, which must be taken into account during the next IUCN Red List regional assessment. In addition, the goliath grouper should be included in the Mexican list for endangered species (NOM-059-SEMARNAT).

Spatial ecology of Nassau Grouper at home reef sites: using acoustic telemetry to track a large, long-lived epinephelid across multiple years (2005-2008)

Characterizing the behavior of coral reef fishes at home reef sites can provide insight into the mechanisms of spatial ecology and provide a framework for spatial resource management. In the Caribbean, populations of Nassau grouper Epinephelus striatus have declined due to fishing impacts on spawning aggregations. Despite local and regional efforts by fisheries managers to implement regulations protecting spawning aggregations, few Nassau grouper populations appear to be recovering. In order to improve management strategies for this critically endangered species, it is necessary to understand the spatial ecology of the species across seasons and years. In the Cayman Islands, we used a multi-year, presence/absence, depth-coded acoustic tagging dataset of Nassau grouper to characterize patterns in the species’ behavior and vertical habitat use at home reef sites. Twenty acoustically tagged individuals (56-84 cm, 70.01 ± 7.40 cm; total length, mean ± SD) maintained consistent home reef sites, although some fish regularly shifted activity centers within the home site, often following a seasonal spawning migration. Seven fish with depth-coded tags showed a higher probability of vertical movement in the hours immediately following dawn and preceding dusk. We found evidence of a positive relationship between the fish condition factor and depth of home reef site. The finding of persistent home reef sites across years suggests that properly sized spatial reserves at home reef sites can be a useful complement to spawning aggregation protection when considering management strategies for Nassau grouper.

Modelling the effect of vaccination on transmission dynamics of nervous necrosis virus in grouper larvae Epinephelus coioides.

Nervous necrosis virus (NNV) infection in susceptible grouper larvae has been reported to cause high mortalities, leading to great economic losses in aquaculture industry. Although the effects of NNV vaccines on grouper have been broadly investigated, vaccination strategies have not been fully established. To this end, we introduced the parsimonious epidemiological models that explored the assessment of key epidemiological parameters and how they changed when vaccinations showed the effects. We showed that the models capture the published cumulative mortality data accurately. We estimated a basic reproduction number R0 =2.44 for NNV transmission in grouper larvae without vaccination. To effectively control NNV transmission by vaccination, a model for disease control was also generalized to attain the goals of controlled reproduction number less than 1. Our results indicated that at least 60% of grouper population needed to be immunized for ~75min. Our data-driven modelling approach that links the transmission dynamics of NNV and vaccination strategies for grouper has the potential to support evidence-based planning and adaptation of integrated control measures. We encourage that the epidemiology-based framework introduced here can be further implemented for establishing effective vaccination and mitigation actions aimed at controlling diseases in fish farming practices.