Recruitment Of Reef Fishes Research Articles

Anomalous sea temperatures can impair coral reef fish recruitment

Understanding how temperature affects coral reef fish recruitment success is crucial for assessing impacts of ocean warming on coral reef resilience. We utilized a long-term fish survey dataset along the west coast of Hawai‘i Island to investigate the role of sea surface temperature (SST) in influencing recruitment timing and density. The dataset consisted of 17 years of surveys, with 25 sites annually surveyed in the months of May, July, September and November. We found that peak recruitment, i.e. the maximum number of recruits recorded across all surveys per year, usually occurred during July surveys. For sites where peak recruitment for that year occurred outside July, there were significantly fewer fish recruits than for sites whose peak recruitment occurred in July. In addition, the timing of peak recruitment is influenced by anomalously warm or cool years prior to spawning. The decrease in recruit density outside these times is likely influenced by recruits being exposed to temperatures warmer and cooler than their optimum. Our results show that climate variability is having an impact on the timing of peak recruitment, creating a mismatch between the thermal optimum of developing recruits and the thermal environment they develop in, negatively affecting recruit density in critical coral reef habitats. Altered and reduced recruitment has the potential to disrupt reef community structure and long-term fisheries sustainability in Hawai‘i, with important management implications for coral reefs in the future.

Effects of habitat fragmentation on the recruitment and early post-settlement survival of coral reef fishes

The combined effects of global climate change and local anthropogenic stressors are leading to increasing loss and fragmentation of habitats. On coral reefs, habitat loss has been shown to influence the abundance and composition of associated fish assemblages, yet few studies have considered how habitat fragmentation may influence reef fish populations and assemblages. Herein, we compared survival, growth and recruitment of reef fish among experimental patches composed of six similar sized colonies of finely branching Pocillopora spp. but with different degrees of fragmentation: coral colonies were clumped (unfragmented), divided into two groups (low fragmentation), three groups (moderate fragmentation) or six groups (high fragmentation). Thirty settlement-stage Pomacentrus amboinensis were tagged, released onto each of the experimental patches, and their survival monitored daily for 11 days. Abundance and species richness of all reef fishes that subsequently recruited to the patches were also recorded, and used to analyse recruitment and community composition. There were no detectable differences among fragmentation treatments in the abundance or composition of reef fish assemblages that recruited to the patches, however, fragmentation influenced the survivorship of P. amboinensis. Highest survival of P. amboinensis was recorded on the unfragmented patches (61%.11 days−1) and highly fragmented habitat patches (54%.11 days−1) and lowest survival on low and moderate fragmentation treatments (47% and 48%.11 days−1, respectively). This suggests that there may be multiple competing processes that moderate mortality (e.g., predation) in unfragmented versus highly fragmented habitats, with moderate levels of habitat fragmentation having the greatest influence on the early post-settlement survival of corsal reef fish.

Year-round high abundances of the world\u2019s smallest marine vertebrate (Schindleria) in the Red Sea and worldwide associations with lunar phases

Very little is known about the ecology and biology of the smallest marine vertebrates, fishes in the genus Schindleria. Even though over half of named Schindleria species have been identified in the Red Sea, the collection of only very few specimens has been documented. Here, we assessed abundance patterns of nearly two thousand Red Sea long dorsal fin (LDF) adults and found evidence for putative seasonal and spatial differences, likely related to differing habitat and environmental conditions. The highest abundances were outside local seasonal temperature extremes and decoupled from peaks of coral reef fish recruitment. We also found evidence for global trends in abundances related to lunar cycles using our Red Sea data and that from a recently published large collection of specimens from the DANA Expedition (1928–1930). The abundance of adult LDF Schindleria in relation to lunar phases differed significantly, with most Schindleria caught outside the full moon, and mostly during the new moon in the Red Sea and the 3rd quarter moon in the DANA collection. We further suggest that the abundances of Schindleria at coral reefs may be related to reproductive cycles and that these cycles may be timed with the moon as back-calculations of hatch dates from otoliths from the Red Sea significantly resulted after the new moon, making Schindleria the fastest-lived coral reef fish with the shortest generation times. Schindleria could be the most numerous coral reef fish in the world, for which we encourage increased research.

USING AGGREGATING DEVICES TO SAMPLE FISH RECRUITS AROUND DEEP SHIPWRECKS: EXPERIMENTS AND SUGGESTIONS

Fish aggregating devices (FAD) are an ancient fishery technique that benefits from the gregarious behavior of many species. They represent alternatives to usual census approach to study fish recruits. Based on this, we test two FAD models built for fish recruitment research, Standard monitoring unit for the recruitment of reef fishes (SMURF) and Artificial Reef Mooring (ARM) moored for the first time close to deep shipwrecks inBrazil Northeastern coast. We compared fish recruits’ abundance sampled by both models at two depths, bottom and mid-water (6 meters from the bottom). SMURFs sampled seven times more fish recruits than ARM with no difference between depth. We discovered that SMURFs mooring tilted 24º in mean with local marine currents. A long-term study with SMURFs tested immersion time influence in recruit’s sampling, and explored recruit’s abundance and standard length at two depth from the bottom. Increasing immersion timefrom 14-28 days did not influence recruit’s abundance. Bottom and Mid-water SMURFs sampled equal recruit’s number and fish sizes were significantly larger at the bottom. FADs, specially SMURFs, showed good tool to sample fish recruits in deeper shipwrecks,however standardization of FAD deployment is indicated to maximize work time and security in unstable sea conditions.

Patterns of juvenile reef-fish recruitment in Kenya’s shallow fringing- lagoon reefs

Studies to understand local-scale patterns in the recruitment of juvenile coral-reef fishes within the western Indian Ocean (WIO) region are few, yet such knowledge is important in fisheries management. Underwater visual census surveys were conducted at five shallow fringing-lagoon reef sites along the Kenyan coast, between June 2012 and March 2016, to quantify patterns in the abundance of new recruits and juveniles. Recruitment was observed year-round, with a consistent pronounced seasonal peak in recruit densities and species richness during December to April of each year, which was strongly correlated with high sea temperatures. Annual variations in recruitment were also observed, with a higher recruitment peak in 2013 as compared with in other years. A total of 112 species belonging to 19 families were identified, dominated by species belonging to the Pomacentridae, Labridae and Apogonidae, which altogether represented 91% of the total number of recruits recorded. The species with the largest number of recruits (Chromis viridis, Thalassoma hebraicum and Gomphosus caeruleus) showed evidence of year-round recruitment, although the timing of recruitment peaks was not consistent. Multivariate analysis of the species composition separated mainland from offshore fringing-reef sites, and also revealed strong habitat associations, pointing towards increasing recruit abundance with increasing live hard-coral cover and rugosity. Live hard-coral cover, which constituted an average of 21%, was associated with 63% of the total number of recruits recorded. This study contributes new insight into local-scale patterns of juvenile reef-fish recruitment in Kenya and the WIO region, and demonstrates the important nursery function of shallow fringing-lagoon reefs.

Climatic conditions and nursery habitat quality provide indicators of reef fish recruitment strength

AbstractIdentifying and protecting nursery habitats for species is a key conservation strategy for the long‐term sustainability of populations. In tropical ecosystems, macroalgal habitats have recently been identified as nurseries for fish of commercial and conservation significance. Here, we explore how local‐scale variations in seaweed habitat quality interact with large‐scale climatic conditions (Southern Oscillation Index, SOI) to influence the recruitment of three tropical fish species (Lethrinus spp.), often targeted by fishers. New fish recruits and juveniles of all species were almost exclusively found in macroalgal nursery habitats, while adults of two of these species were predominantly found on adjacent coral reefs. Annual supply rates of new recruits were found to be strongly correlated to variations in the SOI, with La Nina conditions associated with higher recruitment. However, local rates of recruitment were generally poor predictors of older juvenile abundance. Instead, local juvenile abundance was more closely related to structural characteristics of macroalgae nursery habitat quality (density, canopy height, canopy cover) and/or predator biomass, at the time of survey, with species‐specific habitat associations apparent. Given the dynamic nature of fish recruitment supply to the SOI, coupled with the effects of climatic and oceanic processes on the structure of macroalgal patches, these results suggest protection of macroalgal nursery habitats that maintain high canopy density, height and cover is critical to supporting the conservation of fish populations.

Recruitment Patterns of Juvenile Fish at an Artificial Reef Area in the Gulf of Mexico

AbstractIn 2011 the Texas Parks and Wildlife Department and the Coastal Conservation Association of Texas deployed over 4,000 concrete culverts in a designated artificial reef area off Port Mansfield, Texas, to enhance habitat for sport fish species in the Gulf of Mexico. A study was conducted to assess juvenile fish recruitment at varying culvert densities within the artificial reef area. Standard monitoring units for the recruitment of reef fish (SMURFs) were used to sample juvenile fish, and these collections were compared with visual scuba surveys. The 0.027‐m3 SMURFs were placed at four different culvert densities (0, 1–50, 51–100, and 101+ culverts in a 30‐m radius) and sampled during 2013 to 2014. Measurements of rugosity, vertical relief, and percent cover were collected to elucidate factors that drive juvenile recruitment. Average species richness was highest at sites with no culverts and lowest at dense culvert sites. Species compositions were significantly different between sampling locations with no culverts and all locations with culverts; average similarity was 33.8%. Belted Sandfish Serranus subligarius was the most ubiquitous species among all sampling locations. Visual scuba surveys at the same locations showed lower diversity indices of the juvenile fish community than observed by SMURFs and were only 14% similar to the community sampled by the SMURFs. These findings suggest SMURFs are a more effective tool for examining juvenile fish at an artificial reef due to the cryptic nature of juveniles and the low visibility around shallow reefs. Additionally, commercially important Yellowedge Grouper Hyporthodus flavolimbatus, Warsaw Grouper H. nigritus, and Red Snapper Lutjanus campechanus juveniles were only found at SMURFs at sampling locations with no culverts. The presence of juveniles of these key species suggest that fisheries management may benefit from creating low‐relief reef patches away from the main reef where juvenile fish can recruit and grow.

Ocean Productivity May Predict Recruitment of the Rainbow Wrasse (Coris julis).

Predicting recruitment fluctuations of fish populations remains the Holy Grail of fisheries science. While previous work has linked recruitment of reef fish to environmental variables including temperature, the demonstration of a robust relationship with productivity remains elusive. Despite decades of research, empirical evidence to support this critical link remains limited. Here we identify a consistent and strong relationship between recruitment of a temperate wrasse Coris julis, from temperate reefs in the mid-Atlantic region, with Chlorophyll, over contrasting scales, across multiple years. Additionally, we find that the correlation between Chlorophyll and recruitment is not simply masking a temperature-recruitment relationship. Understanding the potential mechanisms underlying recruitment variability, particularly as it relates to changing climate and ocean regimes, is a critical first step towards characterizing species’ vulnerability to mismatches between pulsed planktonic production and early pelagic life stages.

Early life history of larvae and early juvenile Atlantic horse mackerel Trachurus trachurus off the Portuguese west coast

Early life history traits (ELHTs) are key to understand recruitment patterns in marine animals. However, for reef fishes, studies on ELHTs are mainly focused on tropical systems and little is known for temperate reefs. In this study we used SMURFs (Standard Monitoring Units for the Recruitment of Reef Fishes) to collect fish in a temperate rocky reef system (Arrábida Marine Park, Portugal) on a weekly basis for three months during the recruitment period. Six sub-surface SMURFs sampled 2490 Atlantic horse mackerel (Trachurus trachurus) postlarvae and juveniles. Sagittal and lapilli otoliths were extracted from a subsample of 296 fish and ELHTs, such as size and age at settlement, growth rate and age at first secondary growth formation were examined. Additionally, we tested three growth curves and selected the best suited to back-calculate the hatching pattern based on the lengths of all sampled fish. Standard length ranged from 6.13mm to 48.56mm and subsampled fish were aged between 19days to 44 days. Age and size at settlement were estimated between 19days and 36days for individuals of 6.13mm and 24.95mm, respectively. Otolith shape changed clearly with increasing age and, on average, secondary growth started to form on day 33 (±3 days). Age/length relationship was well described by a Gompertz growth model which was used to back-calculate hatching dates. Four distinct hatching cohorts were identified with fish of the earliest cohort showing a faster body and otolith growth. This study indicates that the nearshore environment might have an important role in the early growth, development and hence recruitment of Atlantic horse mackerel. Information on the early life history of Atlantic horse mackerel is key to understand recruitment processes for this economically and biologically important species.

Influences of oceanographic and meteorological features on reef fish recruitment in Hawai’i

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 463:259-272 (2012) - DOI: https://doi.org/10.3354/meps09838 Influences of oceanographic and meteorological features on reef fish recruitment in Hawai’i Helen E. Fox1,*,**, Kelly M. Haisfield1,2,**, Michael S. Brown3, Todd C. Stevenson4, Brian N. Tissot4, William J. Walsh5, Ivor D. Williams6 1Conservation Science Program, World Wildlife Fund − US, Washington, DC 20037-1132, USA 2Sustainable Development and Conservation Biology Program, University of Maryland, College Park, Maryland 20742, USA 3Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2 4School of Earth and Environmental Sciences, Washington State University, Vancouver, Washington 98686, USA 5Division of Aquatic Resources, State of Hawai’i, Honokohau Marina, Kailua-Kona, Hawai’i 96704-8807, USA 6Joint Institute for Marine and Atmospheric Research, University of Hawai’i at Manoa, Honolulu, Hawai’i 96822, USA *Email: helen.fox@wwfus.org**These authors contributed equally to this work ABSTRACT: Larval fish recruitment is generally highly variable in space and time, and can significantly influence adult population abundance, density and distribution, as well as community structure in coral reef systems. We investigated relationships between reef fish recruitment (data from the West Hawai’i Aquarium Project) and oceanographic and meteorological variables (measures of eddy presence and frequency, El Niño Southern Oscillation, sea surface temperature, sea surface height, chlorophyll a concentration and rainfall). We compared these variables at different time scales—monthly and annually—to substantiate 1 of 3 possible hypotheses about the relationship between eddies and other oceanographic features and fish recruitment: (1) they are positively correlated, indicating that eddy activity could enhance recruitment; (2) they are negatively correlated, indicating that eddy activity may reduce or inhibit recruitment; and (3) they are not correlated, indicating that eddy activity has no impact on recruitment. We found several potential linkages generally supporting the hypothesis that eddies negatively correlate with fish recruitment. In contrast to previous work, we found significant negative correlations in annual patterns of cold-core mesoscale eddies and young-of-the-year totals on the west coast of the island of Hawai’i. We also investigated time lags between monthly recruitment data and oceanographic data several months earlier, consistent with planktonic larval duration of Zebrasoma flavescens and Ctenochaetus strigosus; these phase shifts also produced negative correlations. Our results are exploratory and are only correlations, and thus do not suggest causation; further exploration is needed to substantiate the possibility that eddies have a negative influence on reef fish recruitment. However, these results do call into question that eddies in west Hawai’i have a positive impact on fish recruitment, a theory that has persisted in the literature for nearly 30 yr. KEY WORDS: Mesoscale eddy · Planktonic fish larvae · Fish replenishment area · FRA · Marine protected area · MPA · West Hawai’i Aquarium Project · WHAP Full text in pdf format PreviousNextCite this article as: Fox HE, Haisfield KM, Brown MS, Stevenson TC, Tissot BN, Walsh WJ, Williams ID (2012) Influences of oceanographic and meteorological features on reef fish recruitment in Hawai’i. Mar Ecol Prog Ser 463:259-272. https://doi.org/10.3354/meps09838 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 463. Online publication date: August 30, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Interactive effects of live coral and structural complexity on the recruitment of reef fishes

Corals reefs are subjected to multiple disturbances that modify levels of coral cover and structural complexity of the reef matrix, and in turn influence the structure of associated fish communities. With disturbances predicted to increase, insight into how changes in substrate condition will influence the recruitment of many fishes is essential for understanding the recovery of reef fish populations following biological and physical disturbances. While studies have revealed that both live coral cover and structural complexity are important for many fishes, there is a lack of understanding regarding how a combination of these changes will impact the recruitment of fishes. This study used experimentally constructed patch reefs consisting of six different habitat treatments; three levels of live coral cover (high, medium, low) crossed with two levels of structural complexity (high, low), to test the independent and combined effects of live coral cover and structural complexity on the recruitment and recovery of fish communities. The abundance and species diversity of fishes varied significantly among the six habitat treatments, but differences were not clearly associated with either coral cover or structural complexity and varied through time. More striking, however, was a significant difference in the composition of fish assemblages among treatments, due mostly to disproportionate abundance of coral-dwelling fishes on high coral cover, high complexity reefs. Overall, it appears that coral cover had a more important influence than structural complexity, at least for the contrasting levels of structural complexity achieved on experimental patch reefs. Furthermore, we found that live coral cover is important for the recruitment of some non-coral-dependent fishes. This study confirms that live coral cover is critical for the maintenance of high biodiversity on tropical coral reefs, and that sustained and ongoing declines in coral cover will adversely affect recruitment for many different species of reef fishes.

Influence of marine reserves on reef fish recruitment in the upper Florida Keys

Coral reef fish recruitment to the upper Florida Keys was monitored monthly for 7 years (2003–2009) to establish a baseline and test whether recruitment varied between reserve and non-reserve sites. Recruits <30 days old were surveyed in two primary habitat types (reef and rubble) in each of two replicate reserve and non-reserve sites. Recruitment of all fish species peaked in the summer and early fall; winter recruitment was consistently low. Some interannual recruitment patterns were roughly similar among species, with recruitment generally lower in 2004 for several taxa, possibly reflecting a system-wide process. During 7 peak recruitment months each year, overall recruitment to reef habitat was significantly higher in non-reserve sites in 2 of 7 years. In contrast, recruitment to rubble habitat was significantly higher in reserves in 3 of 7 years. Specific fish taxa had variable patterns of recruitment to reserves and non-reserves: Despite high interannual variation in recruitment magnitude, Scaridae (parrotfish) densities were significantly higher in reserves than in non-reserves. Densities of two abundant goby taxa (Gnatholepis thompsoni and Coryphopterus spp.) were also higher in reserves than in non-reserves, but the magnitude varied among years. Recruitment of the bicolor damselfish, Stegastes partitus, did not differ consistently between reserves and non-reserves. Densities of Thalassoma bifasciatum had an opposite trend relative to other taxa, with densities typically higher in non-reserves than in reserves (in 6 of 7 years; significant in only 2 years). Higher recruit densities (scarids, gobies, and all rubble taxa together) within reserves were coupled with significantly lower densities of intermediate-sized piscivores and significantly greater cover of Dictyota spp. macroalgae and turfs relative to non-reserves. Reserves may be areas of relative refuge from predation for some fish recruits due to a combination of reduced predator abundance and enhanced small-scale structural habitat.

Fisher behaviour influences catch productivity and selectivity in West Hawaii's aquarium fishery

Abstract Stevenson, T. C., Tissot, B. N., and Dierking, J. 2011. Fisher behaviour influences catch productivity and selectivity in West Hawaii's aquarium fishery. – ICES Journal of Marine Science, 68: 813–822. In 1999, marine protected areas (MPAs) were implemented along the west coast of the Big Island of Hawaii, closing ∼35% of the coastline to aquarium fishing. Catch per unit effort and total catch of the most commonly targeted fish, yellow tang (Zebrasoma flavescens), have increased since the implementation of the MPAs, yet its abundance has declined by 45% in areas open to aquarium fishing between 1999 and 2007. How effort allocation, harvesting efficiencies, and job satisfaction influence catch productivity and selectivity in West Hawaii's aquarium fishery are investigated, and how these dynamics explain the discrepancy between catch rates and relative abundance for yellow tang is discussed. Cross-sectional fisher questionnaires, semi-structured fisher interviews, and in situ and ex situ catch analyses were performed. The results indicate that fishers dive deeper when reef fish recruitment is perceived as weak, increase harvest efficiency with larger fishing teams, and intensively harvest “coral-friendly” reef fish to supply the global aquarium fish trade. Experienced fishers were less likely to exit the fishery, and job satisfaction was high despite declining fish stocks. These findings may help explain harvesting efficiencies and fleet investment, underscore the importance for evaluating fisher behaviours, and have potential management implications for other aquarium fisheries.

Transport of reef lizardfish larvae by an ocean eddy in Hawaiian waters

Competent (settlement-stage) larvae of the lizardfish, Trachinocephalus myops were collected from one ocean location (near a coral reef) at times before and during a mesoscale ocean eddy event. Mesoscale ocean eddies occur periodically at this location, offshore of the island of Hawaii. Larval age was younger ( t-test, P < 0.0001) for lizardfish collected at the time when a cyclonic mesoscale eddy dominated the offshore ocean flow field. This result supports two important notions: (1) that reef fish larvae have flexibility in the age at which they can transition to the reef habitat and (2) that offshore deep-sea ocean currents can be influential in larval reef fish recruitment.

Climatic influence on reef fish recruitment and fisheries

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 410:283-287 (2010) - DOI: https://doi.org/10.3354/meps08695 NOTE Climatic influence on reef fish recruitment and fisheries Octavio Aburto-Oropeza1,*, Gustavo Paredes1, Ismael Mascareñas-Osorio2, Enric Sala2,3 1Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, California 92093-0202, USA 2Centre d’Estudis Avançats de Blanes (CSIC), Blanes, Spain 3National Geographic Society, Washington, DC, USA *Email: maburto@ucsd.edu ABSTRACT: Interannual and interdecadal variability of the recruitment and spawning stock biomass of fish has been observed for many pelagic commercial species. For reef fish, climate variability has been considered only as a pre-recruitment factor that has stochastic impacts on the survival of eggs and larvae during their pelagic stage. Here we show that fisheries landings of reef fish are related to climatic conditions that occurred at the time of settlement. Using detailed studies on the life history of 2 important commercial species (yellow snapper and leopard grouper) and a compilation of landing statistics over 11 yr in the Gulf of California, we established that increasing recruitment translated into greater fisheries landings and increased revenue once individuals recruited into fishery stocks. Recruitment appeared to be modulated by El Niño/La Niña events. Monitoring of reef fish recruitment could be used to adapt artisanal fisheries management ahead of time, allowing regulation of effort or setting of quotas based on the variability of climate indices. KEY WORDS: Yellow snapper · Lutjanus · Leopard grouper · Mycteroperca · Fisheries revenue · Multivariate ENSO index Full text in pdf format PreviousCite this article as: Aburto-Oropeza O, Paredes G, Mascareñas-Osorio I, Sala E (2010) Climatic influence on reef fish recruitment and fisheries. Mar Ecol Prog Ser 410:283-287. https://doi.org/10.3354/meps08695 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 410. Online publication date: July 14, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

Patterns of recruitment of coral reef fishes in a monsoonal environment

The abundance of newly settled recruits of coral reef fishes was monitored at a total of 11 sites at two islands and two coastal locations in the central Philippines for a 20-month period (February 2008 to September 2009) that included two monsoon cycles. Recruitment occurred throughout the year. Most of the abundant species exhibited protracted recruitment seasons. This confirms the expectation of extended breeding of reef fishes at lower latitudes. The annual pattern of recruitment of reef fishes as a group was predictable. Annual fluctuations of sea surface temperature and wind strength largely explained the pattern. Rainfall, however, did not significantly influence the pattern of recruitment. Peaks in density and species richness of recruits occurred during the southwest monsoon and the second inter-monsoonal period of the year (July to October) when temperatures were highest and when most of the sites were sheltered from winds or when winds were weak. Conversely, lowest density and species richness were observed during the northeast monsoon (November to March) when temperatures were lowest and most sites were exposed to winds. The same pattern could also be seen in the recruitment of both damselfishes (Pomacentridae) and wrasses (Labridae), notwithstanding a tenfold difference in abundance of recruits between the two families. The pattern was fairly consistent across most sites, among most of the species that were examined, and between the 2 years that were sampled. This study is one of the few to provide insights into the influence of environmental factors on the recruitment patterns of fishes on Indo-Pacific coral reefs situated at lower latitudes.

Mangrove use by the invasive lionfish Pterois volitans

Lionfish Pterois volitans are successful invasive predators in the sub-tropical and tropi- cal Western Atlantic. Their invasion of coral reef ecosystems is a major conservation concern, as pre- vious studies in the Western Atlantic have found that this top predator (1) occurs at higher densities and forages more successfully than in its native range, (2) lacks significant predators as an adult, and (3) reduces reef fish recruitment. The effects of lionfish on coral reef communities have been exam- ined, but it is not known if these predators use critical non-reef habitat such as mangroves, which serve as nurseries for many reef fish species. To investigate lionfish usage of non-reef critical habitat, we compared population size-structure and stomach contents of P. volitans in mangroves and coral reefs on the island of San Salvador, Bahamas. In each habitat, >80% of lionfish stomachs contained prey items with similar gut content wet weight (0.98 ± 0.35 g in reef habitat and 0.99 ± 0.43 g in man- grove habitat) despite differences in total lionfish length (231.1 ± 10.30 mm in reef habitat and 176.3 ± 16.83 mm in mangrove habitat). Prey items detected by genetic analysis included individuals of the families Palaemonidae, Penaeidae, Gobidae, Scaridae, Mullidae and Grammatidae. These results demonstrate that lionfish colonize and feed in mangrove habitat in the Bahamas. Further study of lionfish outside reef habitat is required to understand the effects of this marine invasion.

Variable temporal relationships between environment and recruitment in coral reef fishes

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 379:225-240 (2009) - DOI: https://doi.org/10.3354/meps07886 Variable temporal relationships between environment and recruitment in coral reef fishes Henri Vallès1,*, Wayne Hunte2, Donald L. Kramer1 1Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, Quebec H3A 1B1, Canada 2Department of Biological and Chemical Sciences, University of the West Indies, Cave Hill Campus, University Drive, Cave Hill, St. Michael, Barbados *Email: hevals@gmail.com ABSTRACT: Studies of coral reef fish recruitment have focused more on factors influencing the return of larvae to reefs and the process of settlement than on factors affecting survival in the plankton, despite the well-documented importance of the larval environment for temperate marine species. We examined the ability of environmental factors to explain temporal patterns of recruitment in 8 taxa of coral reef fishes, distinguishing variables associated with settlement from those associated with the pelagic larval stage. At 10 d intervals over a 17 mo period, we collected newly settled fishes from settlement units in Barbados (West Indies). We collected concurrent data on 3 settlement-associated variables, lunar darkness, wind speed, and tidal amplitude, and 5 larval environment variables, sea-surface temperature, cloud cover, salinity, chlorophyll a concentration, and normalized water-leaving radiance at 555 nm. The last 3 were associated with low-salinity intrusions originating in the Amazon. We used hierarchical partitioning and Mallow’s C(p) model selection to identify important variables for each taxon. Temporal patterns of recruitment differed among taxa of which 6 showed significant environmental correlations. Significant settlement variables included lunar darkness and tidal amplitude. Significant larval environment variables were diverse and varied in magnitude and sign across taxa. The effects of larval variables were generally strong relative to settlement variables. The temporal scale of the strongest environmental predictor differed across taxa. Our study supports the views that planktonic factors affecting larval survival substantially influence recruitment in coral reef fishes and that different species are affected differently by a common, temporally variable, planktonic environment. KEY WORDS: Settlement · SMURF · Rubble · Pomacentridae · Labridae · Serranidae · Scaridae · Gobiidae Full text in pdf format PreviousNextCite this article as: Vallès H, Hunte W, Kramer DL (2009) Variable temporal relationships between environment and recruitment in coral reef fishes. Mar Ecol Prog Ser 379:225-240. https://doi.org/10.3354/meps07886 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 379. Online publication date: March 30, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Possible effects of downwelling on the recruitment of coral reef fishes to the Eilat (Red Sea) coral reefs

We compared water current measurements with data on the recruitment of reef fishes to a coral reef in Eilat, Red Sea for two consecutive recruitment seasons. There was a clear correlation between the daily number of recruits and the magnitude of the downwelling flow, suggesting that an increase in offshore (near bottom) flow induces higher recruitment. The higher recruitment may be the result of larval swimming against the flow. Although the exact mechanism explaining this correlation is unclear, it may involve odor transport from the reef by the downwelling currents, which reaches competent larvae in deeper water and directs them to potential settlement sites.

Predictability of reef fish recruitment in a highly variable nursery habitat.

There has been a lengthy debate on whether the abundance of adult reef fishes depends on prerecruitment or postrecruitment processes; however, we still do not have the ability to predict the magnitude of local fish recruitment. Here we show that the success of the leopard grouper (Mycteroperca rosacea) recruitment in the Gulf of California, Mexico, is determined by the availability of nursery habitat, which in turn is strongly correlated to climate conditions. Observational and experimental studies showed that leopard grouper larvae recruit preferentially on shallow rocky bottoms with brown algal (Sargassum spp.) beds, and that abundance of recruits is determined by the availability of Sargassum. The biomass of Sargassum decreases linearly with an increase in the Multivariate El Niño Southern Oscillation (ENSO) Index (MEI; an index positively correlated with water temperature and negatively correlated with nutrient availability). We analyzed the relationship between the interannual variation of MEI and the recruitment of the leopard grouper using field estimates of abundance of juvenile groupers. Our results show that there is a nonlinear relationship between recruitment and the oceanographic climate, in that the density of recruits decreases exponentially with increasing MEI. The predictability of leopard grouper recruitment has important implications for fisheries management, since it could allow adaptive management without expensive stock assessment programs.