Reefs Of Barbados Research Articles

Making the most of data-poor fisheries: Low cost mapping of small island fisheries to inform policy

Data scarcity in small-scale fisheries hinders the effective management of marine resources. This is particularly true within small island developing states that often have limited capacity for monitoring activities that could inform policy decisions. This study estimates the spatial distribution of fishing activity in the data-poor nearshore reef fisheries of Barbados using low cost interview surveys of fishers combined with a geospatial platform. With data from over 150 fishers in the island's major reef fisheries, the estimated total annual yield ranged from 272.6 to 409.0mt, with seine fishing accounting for 65% of landings. This estimate is substantially higher than the recorded landings in official databases. Fishing activity is concentrated on the sheltered and heavily populated West Coast of the island. Reef fishing effort decreases markedly during the months associated with the offshore pelagic fishery season, as many fishers switch fisheries during this time and rough sea conditions restrict access to the nearshore windward reefs. The high levels of fishing intensity and low yields per unit of reef area appear to validate anecdotal evidence that the nearshore reefs of Barbados are heavily overexploited. The qualitative nature of interview data and other data gaps hinder the precise estimation of fishing effort and yield, where relative values are likely to be more accurate than absolute values. Nonetheless, the spatially and temporally explicit data generated here demonstrates how simple cost-effective methods can be used to fill important information gaps for marine resource management and spatial planning.

Reply to comment by E. Bard et al. on “Younger Dryas sea level and meltwater pulse 1B recorded in Barbados reef crest coral Acropora palmata” by N. A. Abdul et al.

AbstractAbdul et al. (2016) presented a detailed record of sea level at Barbados (13.9–9 kyr B.P.) tightly constraining the timing and amplitude during the Younger Dryas and Meltwater Pulse 1B (MWP‐1B) based on U‐Th dated reef crest coral species Acropora palmata. The Younger Dryas slow stand and the large (14 m) rapid sea level jump are not resolved in the Tahiti record. Tahiti sea level estimates are remarkably close to the Barbados sea level curve between 13.9 and 11.6 kyr but fall below the Barbados sea level curve for a few thousand years following MWP‐1B. By 9 kyr the Tahiti sea level estimates again converge with the Barbados sea level curve. Abdul et al. (2016) concluded that Tahiti reefs at the core sites did not keep up with intervals of rapidly rising sea level during MWP‐1B. We counter Bard et al. (2016) by showing (1) that there is no evidence for a hypothetical fault in Oistins Bay affecting one of the Barbados coring locations, (2) that the authors confuse the rare occurrences of A. palmata at depths >5 m with the “thickets” of A. palmata fronds representing the reef‐crest facies, and (3) that uncertainties in depth habitat proxies largely account for differences in Barbados and Tahiti sea level differences curves with A. palmata providing the most faithful proxy. Given the range in Tahiti paleodepth uncertainties at the cored sites, the most parsimonious explanation remains that Tahiti coralgal ridges did not keep up with the sea level rise of MWP‐1B.

Ecological assessments of the coral reef communities in the Eastern Caribbean and the effects of herbivory in influencing coral juvenile density and algal cover

AbstractCaribbean reefs have been unevenly surveyed, with many areas lacking baseline data. In this study, the current status of Orbicella reefs, a structurally complex forereef habitat, was quantified in an understudied region, the Eastern Caribbean. During 2011 the same observers surveyed benthic assemblages, coral juvenile density, herbivorous fishes, and invertebrates at 30 Orbicella reefs in four Eastern Caribbean areas: Antigua, Barbados, St Lucia, and St Vincent and the Grenadines (hereafter St Vincent). Not all Orbicella forereefs were functionally the same in the Eastern Caribbean. Benthic communities and herbivorous fishes varied greatly among islands. Hard coral had the highest overall percent cover on most reefs in this study, with an average cover of 22%, and was greater than fleshy macroalgal cover at 83% of the sites. Overall, coral juvenile density was low but was positively associated with higher densities of Diadema antillarum, highlighting the importance of herbivory on the reefs. Nearshore coral reefs in Barbados were in a better state than other areas, exhibiting higher coral cover dominated by spawning corals, higher densities of coral juveniles exhibiting higher coral cover dominated by spawning corals, higher densities of coral juveniles and D. antillarum. Low biomass of herbivorous fishes at a majority of the coral reef sites is of major concern for the functioning of these reefs. Conservation of parrotfishes and other herbivores is necessary given the abundance of algae on most of these reefs and the beneficial effect of their presence on coral juveniles. This is the first comprehensive study that compares the state of Orbicella reefs in the Eastern Caribbean, providing valuable information that will be useful in creating realistic targets for future management and conservation.

Younger Dryas sea level and meltwater pulse 1B recorded in Barbados reef crest coral Acropora palmata

AbstractThe Younger Dryas climate event occurred during the middle of the last deglacial cycle and is marked by an abrupt shift in the North Atlantic polar front almost to its former glacial position, trending east to west. Using high‐precision and high‐accuracy U‐Th‐dated Barbados reef crest coral, Acropora palmata, we generate a detailed sea level record from 13.9 to 9000 years before present (kyr B.P.) and reconstruct the ice volume response to the Younger Dryas cooling. From the mid‐Allerød (13.9 kyr B.P.) to the end of the Younger Dryas (11.65 kyr B.P.), rates of sea level rise decreased smoothly from 20 mm yr−1 to 4 mm yr−1, culminating in a 400 year “slow stand” before accelerating into meltwater pulse 1B (MWP‐1B). The MWP‐1B event at Barbados is better constrained as beginning by 11.45 kyr B.P. and ending at 11.1 kyr B.P. during which time sea level rose 14 ± 2 m and rates of sea level rise reached 40 mm yr−1. We propose that MWP‐1B is the direct albeit lagged response of the Northern Hemisphere ice sheets to the rapid warming marking the end of the Younger Dryas coinciding with rapid warming in the circum‐North Atlantic region and the polar front shift from its zonal to meridional position 11.65 kyr B.P. As predicted by glaciological models, the ice sheet response to rapid North Atlantic warming was lagged by 400 years due to the thermal inertia of large ice sheets. The regional circum‐North Atlantic Younger Dryas climate event is elevated to a global response through sea level changes, starting with the global slowdown in sea level rise during the Younger Dryas and culminating with MWP‐1B. No meltwater pulses are evident at the initiation of the Younger Dryas climate event as is often speculated.

Parrotfish Body Size As An Indicator of Diurnal Fish Species Richness On Fringing Coral Reefs in Barbados

Background: Coral reefs around the world are host to some of the most condensed and varied ecosystems. However, over the past decades, their biodiversity has alarmingly decreased. A rapid and reliable way of assessing their status is urgently needed to monitor and prevent their decline. The purpose of this study is to assess whether or not family Scaridae (common name: parrotfish) body size can be used as an index to evaluate the diurnal fish diversity on coral reefs.
 Methods: We selected 6 accessible reefs on the West coast of Barbados and measured the size of parrotfish we encountered, as well as the number of fish species present on the reef; this data was then plotted and statistically analyzed to establish a possible correlation.
 Results: Our results show that reef fish species richness is strongly correlated to both the ratio of large to small parrotfish and the average parrotfish size. It is however the large to small ratio that exhibited the strongest relationship. Further analysis revealed that the population size of large parrotfish correlates with reef biodiversity with a Pearson’s r coefficient of 0.97.
 Conclusion: This relationship could be due to the fact that large parrotfish (greater than or equal to 20 cm) have increased grazing rates compared to smaller ones, this increased grazing promotes coral polyp recruitment, thereby benefiting the diversity observed on coral reefs. Further research is needed to elucidate whether these results can be extended to other areas of the Caribbean and provide conservation efforts with an easy tool to survey and protect coral reef ecosystems.

The Relationship between Diver Experience Levels and Perceptions of Attractiveness of Artificial Reefs - Examination of a Potential Management Tool

Artificial reefs are increasingly used worldwide as a method for managing recreational diving since they have the potential to satisfy both conservation goals and economic interests. In order to help maximize their utility, further information is needed to drive the design of stimulating resources for scuba divers. We used a questionnaire survey to explore divers’ perceptions of artificial reefs in Barbados. In addition, we examined reef resource substitution behaviour among scuba divers. Divers expressed a clear preference for large shipwrecks or sunken vessels that provided a themed diving experience. Motives for diving on artificial reefs were varied, but were dominated by the chance of viewing concentrated marine life, increased photographic opportunities, and the guarantee of a ‘good dive’. Satisfaction with artificial reef diving was high amongst novices and declined with increasing experience. Experienced divers had an overwhelming preference for natural reefs. As a management strategy, our results emphasize the capacity of well designed artificial reefs to contribute towards the management of coral reef diving sites and highlight a number of important areas for future research. Suggested work should validate the present findings in different marine tourism settings and ascertain support of artificial reefs in relationship to level of diver specialization.

Shelters and Their Use by Fishes on Fringing Coral Reefs

Coral reef fish density and species richness are often higher at sites with more structural complexity. This association may be due to greater availability of shelters, but surprisingly little is known about the size and density of shelters and their use by coral reef fishes. We quantified shelter availability and use by fishes for the first time on a Caribbean coral reef by counting all holes and overhangs with a minimum entrance diameter ≥3 cm in 30 quadrats (25 m2) on two fringing reefs in Barbados. Shelter size was highly variable, ranging from 42 cm3 to over 4,000,000 cm3, with many more small than large shelters. On average, there were 3.8 shelters m−2, with a median volume of 1,200 cm3 and a total volume of 52,000 cm3m−2. The number of fish per occupied shelter ranged from 1 to 35 individual fishes belonging to 66 species, with a median of 1. The proportion of shelters occupied and the number of occupants increased strongly with shelter size. Shelter density and total volume increased with substrate complexity, and this relationship varied among reef zones. The density of shelter-using fish was much more strongly predicted by shelter density and median size than by substrate complexity and increased linearly with shelter density, indicating that shelter availability is a limiting resource for some coral reef fishes. The results demonstrate the importance of large shelters for fish density and support the hypothesis that structural complexity is associated with fish abundance, at least in part, due to its association with shelter availability. This information can help identify critical habitat for coral reef fishes, predict the effects of reductions in structural complexity of natural reefs and improve the design of artificial reefs.

Functional connectivity from a reef fish perspective: behavioral tactics for moving in a fragmented landscape

Functional connectivity, the degree to which the landscape facilitates or impedes movement, depends on how animals perceive costs and benefits associated with habitat features and integrate them into a movement path. There have been few studies on functional connectivity in marine organisms, despite its importance for the effectiveness of Marine Protected Areas. In this study, we asked how open sand and conspecific distribution affected functional connectivity of longfin damselfish (Stegastes diencaeus) on fringing reefs in Barbados. We translocated 102 individuals to sites varying in sand gap width and in configuration: Continuous (solid reef between release site and territory); Detour (sand along the direct path between release site and territory, but an alternative, continuous solid U-shaped reef path); and Patch (sand between release site and territory, but an alternative stepping stone path). We visually tracked and mapped every homing path. We found no evidence of a barrier to movement in the Continuous configuration, but sand was a partial barrier in Detour and Patch configurations. The probability of crossing the sand gap dropped below 50% when its width was > 1.85 m in Detour and > 3.90 m in Patch configuration. Damselfish avoiding large gaps took detours that approximated the route maximizing travel over reef, but they crossed more short sand gaps and fewer conspecific territories, suggesting avoidance of agonistic interactions. This study quantifies for the first time the size and steepness of a barrier to movement in a marine organism, and it provides evidence for effects of both landscape configuration and conspecific distribution on functional connectivity.

Selection of diurnal refuges by the nocturnal squirrelfish, Holocentrus rufus

We examined the diurnal refuges occu- pied by the nocturnal squirrelfish, Holocentrus rufus, to describe refuges and the behavior associated with their use and to determine which, if any, refuge characteristics were selected. We tagged 21 H. rufus on two sites on a fringing reef in Barbados, West Indies, identified the refuges they used (n = 57), measured ten characteristics of each refuge and the surrounding microhabitat, and monitored their refuge use for 4 weeks. To evaluate refuge selection, we measured the same characteristics on a comparable number of unused potential refuges (n = 67) on the same reefs and used classification tree models to determine which characteristics separated used from unused refuges. Each fish used 1-9 refuges, which did not overlap among individuals and were defended against intrusion by conspecifics and some hetero- specifics. Fish with more than one refuge frequently moved among them. There was strong site fidelity with no immigration of untagged fish or emigration of tagged fish on either reef during the study period and no additional refuges being occupied over the 4-week period. Refuges were primarily holes, open at one or two ends, which varied in size, distance from the reef edge, entrance orientation, and vertical relief at the entrance. Holes used as refuges differed significantly from unused holes mainly in characteristics related to the vertical position of their entrance, but the classification tree models differed for the two sites. This study provides the first detailed information on characteristics of daytime refuges used by a noctur- nally active reef fish and the first evidence of selectivity of refuges. It suggests that the abundance and characteristics of holes on reefs could influence the density of H. rufus on natural reefs.

Estimating the density and biomass of moray eels (Muraenidae) using a modified visual census method for hole-dwelling reef fauna

We developed a modified visual census technique suitable for fairly sedentary, hole-dwelling species and used it to determine the diversity, density, biomass, and habitat use of morays at four sites including fringing, patch, and bank reefs in Barbados, West Indies. The method involved a careful search during two passages over transects by day and by night, noting size and position of morays seen, and using the number of new observations on the second passage to estimate the proportion of morays not seen. First passage counts were generally higher than numbers of morays recorded in previous visual censuses. These estimates were raised when we used the time period (day or night) with the highest average density visible for each species, added different individuals from the two passages, and corrected for individuals not seen. We saw more goldentail morays (Gymnothorax miliaris) during the day but more spotted (G. moringa), viper (Enchelycore nigricans), and chestnut (E. carychroa) morays at night. Counts of chain morays (Echidna catenata) did not differ significantly between night and day. Relative abundance and size of moray species varied among sites and to a lesser extent among habitat types within sites, but spotted morays were generally the most important in numbers and biomass. Mean estimated moray density and biomass were much higher than in most previous visual censuses, but similar to rotenone samples on other reefs and comparable to those of other families of predatory fishes. Our findings confirm that morays are abundant and potentially important predators that should be the focus of more attention in ecological studies of coral reefs.

The social organization of adult blue tangs, Acanthurus coeruleus, on a fringing reef, Barbados, West Indies

Blue tangs in Barbados exhibit three distinct social modes: territorial, schooling and wandering. We compared the mobility, foraging, aggression performed and received and the use of cleaning stations of adult blue tangs among modes and among habitats within a single fringing reef in Barbados. Evidence from observed switches during focal observations and multiple observations of tagged individuals indicate that fish are either territorial or non-territorial. Non-territorial fish formed schools and wandered. However, wandering can be used during solitary movements by fish in either type. Fish in the territorial mode, not previously described in adults of this species, restricted activity to a small area overlapping the territories of other tangs. They actively chased conspecifics and were chased mostly by damselfishes. They swam more slowly and fed at higher rates than other modes. Fish in the schooling mode ranged widely in compact, polarized groups of conspecifics, congeners and other species. They were not aggressive and were attacked mostly by damselfishes. They swam rapidly and fed at intermediate rates. Fish in the wanderer mode showed neither aggression nor association with other individuals. They swam rapidly, well above the substrate, fed little, were chased by conspecifics, ocean surgeonfish, A. bahianus, and damselfish and visited cleaning stations more often then other modes. All three modes were observed in all four main zones of the reef, and their behaviour changed quantitatively with habitat type. We suggest that territoriality reduces competition for algal food, schooling allows fish to overcome the food defence by damselfish, tangs and ocean surgeonfish, and wandering permits solitary movement over the reef to cleaning stations, feeding sites and other resources.

Individual differences in microhabitat use in a Caribbean cleaning goby: a buffer effect in a marine species?

Summary Buffer effects occur when changes in population size result in the disproportionate use of poor‐quality habitats. Thus, at low population sizes high‐quality habitats are used preferentially. As population size increases an increasing proportion of the population uses poorer‐quality habitats. Assessment of the temporal and spatial variation in patterns of habitat occupancy can therefore shed light on the differences in quality between habitats and the individual fitness consequences of habitat choice. We provide the first evidence of the potential operation of a buffer effect for a site‐attached marine species. Caribbean cleaning gobies Elacatinus prochilos (Böhlke & Robins) occupy coral and sponge on fringing reefs in Barbados. For adult gobies, resource selection indices suggested a preference for sponge. However, as cleaning goby population size increased, the number of adult cleaning gobies occupying sponge increased more rapidly than the number occupying coral. In contrast, adults preferentially re‐colonized coral following experimental removals and at these low population densities the rate of population increase was greater on coral. Our results suggest that coral may be the preferred habitat, but in Barbados this habitat becomes saturated at very low population densities as a consequence of low client densities and ectoparasite loads. Thus, a larger proportion of the population occupies sponge at most observed population densities. Patterns of habitat occupancy with population size for recruits and juveniles suggest only a small difference in habitat quality between sponge and coral. Indeed, recruits and juveniles do not discriminate between sponge and coral. The population shift towards sponge rather than coral occupancy between recruitment and maturity may arise as a combination of differing survival of recruits and juveniles on coral and sponge and active movement of individuals towards sponge. Our results demonstrate that interactions among individuals are an integral part of population distribution and dynamics and are therefore important in future studies of habitat choice and its associated fitness consequences.

Impact of variable pelagic environments on natural larval growth and recruitment of the reef fish Thalassoma bifasciatum

New recruits of the bluehead wrasse Thalassoma bifasciatum were censused and collected from nearshore reefs of Barbados, West Indies, every 2 weeks for 20 months. Their temporal coincidence with low salinity (<34·5) water during their pelagic larval stage was determined by comparing the otolith records of new recruits with conductivity and temperature records from a current meter moored 2 km off the west coast of the island. Larval residence in a low salinity North Brazil Current (NBC) ring appeared to have a negative impact on growth. Larvae that encountered a NBC ring for at least 7 days during either the first half of the larval period exhibited slower larval growth than those that did not encounter a ring for 7 days during any part of their larval period. As a result of this slower growth, larvae that encountered low salinity waters had a longer pelagic larval duration and were larger at the time of settlement. The magnitude of settlement was not distinctly related to the presence or absence of a NBC ring, but the largest settlement event occurred at the end of the longest ring event. Early juvenile growth did not vary between fish that had encountered a ring and those that did not, so size differences at settlement were propagated through the first week of life on the reef. The potentially opposing attributes of fast and slow‐growing larvae (e.g. fast growing larvae with shorter larval stage duration but smaller size at settlement and higher susceptibility to reef predation), and the resulting differential mortality on the reef may promote the persistence of individuals in the population with contrasting life history traits, and contribute to the lack of a relationship between larval growth and recruitment success. Positive transport related effects of rings (i.e. enhanced retention during some ring events) may further complicate matters by outweighing the negative impact of rings on larval growth.

Individual differences in microhabitat use in a caribbean cleaning goby: a buffer effect in a marine species?

Buffer effects occur when changes in population size result in the disproportionate use of poor‐quality sites or habitats. For species for which direct measurements of fitness differences between individuals are not possible, assessment of the temporal and spatial variations in patterns of habitat occupancy can therefore, shed light on the differences in quality between habitats and the individual fitness consequences of habitat choice. We provide the first evidence of the potential operation of a buffer effect for a site‐attached marine species. Caribbean cleaning gobies Elacatinus prochilos occupy coral and sponge substrata on fringing reefs in Barbados. Cleaning gobies at coral cleaning stations are frequently solitary or found in small groups, and spend 25 times longer cleaning than those on sponge. In contrast, sponge‐dwelling gobies exhibit highly stable, size‐structured dominance hierarchies in which, larger individuals are able to monopolize areas inside the sponge lumen with the highest abundance of the polychaete Haplosyllis spp, a favoured prey item. For adults, resource selection indices suggested a preference for sponge occupancy. As cleaning goby population size increased, however, the number of adult cleaning gobies occupying sponge substrata increased more rapidly than the number occupying coral habitat. Our results suggest that coral may be the preferred habitat, but in Barbados this habitat becomes saturated at very low population densities as a consequence of low client densities and ectoparasite loads. A larger proportion of the population, therefore, occupies sponge at most observed population densities. A population shift towards sponge rather than coral occupancy occurs between recruitment and maturity and may arise as a combination of differing survival of recruits and juveniles on coral and sponge and active movement of individuals towards sponge. Our results demonstrate that behavioural interactions are an integral part of population distribution and dynamics and are therefore, important in future studies of habitat choice and its associated fitness consequences.

SELECTIVE MORTALITY DURING THE LARVAL–JUVENILE TRANSITION IN TWO CORAL REEF FISHES

For organisms with complex life histories, processes occurring during transitions between stages can strongly affect population dynamics. The major life history transition for many marine species is settlement from pelagic larvae to benthic or demersal juveniles. We examined differential mortality at settlement as a function of early life history traits (size-at-age, growth rates) in three cohorts of two common Caribbean coral reef fishes, Thalassoma bifasciatum and Halichoeres bivittatus (Labridae). We deployed light traps to collect late-stage larvae of each cohort. We also collected juveniles of each cohort at regular intervals (every second day) for two weeks following their first appearance on the nearshore reefs of Barbados, West Indies, during the spring (April–May) and fall (August–October) of 1997. Comparisons of otolith-derived traits exhibited by younger recruits (initial group) to those exhibited by older juveniles (survivor group) revealed that there was a difference in otolith growth during ...

Sedimentological Evolution of North Sound, Grand Cayman: A Freshwater to Marine Carbonate Succession Driven by Holocene Sea-Level Rise

ABSTRACT North Sound, Grand Cayman, contains up to 4 m of sediments that accumulated under the influence of the Holocene rise in sea level. Originally, North Sound was a dish-shaped depression formed by the erosion of the Miocene dolostone and Pleistocene limestone bedrock. At that time, a sill along the northern margin isolated the area from the open ocean. Sedimentation from 5,000 to 3,800 yr B.P., which took place in a fresh-water to brackish-water regime, resulted in deposition of the Composite Grain, Gastropod, and Bivalve facies. As sea level rose above the sill, no later than 2,500 yr B.P., marine waters began to invade North Sound and open connections with the Caribbean Sea were established. Peats, which developed in mangrove swamps, were deposited during this transitional phase. Fully marine sedimentation, ongoing for at least the last 2,500 years, resulted in the deposition of the Halimeda, Halimeda-Benthic Foraminifera-Bivalve, and Bivalve-Halimeda facies. Sediment, which accumulated at an average of 85 cm/1000 years, did not keep pace with sea level, which rose at an average of 160 cm/1000 years. As a result, accommodation space in North Sound has progressively increased. A sea-level curve, derived from basal peats and bivalves found in the sediments of North Sound, is comparable to sea-level curves derived for Barbados reefs. For the last 2,500 years, however, the North Sound curve is 3 m lower than a sea-level curve that was derived from peats on Barkers Peninsula, which forms the northwest boundary of North Sound. This discrepancy, attributed to original differences in elevations of the samples, highlights some of the problems associated with the construction and interpretation of sea-level curves. The sedimentary succession in North Sound, which is similar to that found in the Bight of Abaco in the Bahamas, is a record of transient depositional environments that evolved in response to the Holocene rise in sea level.

Territoriality and Habitat Use by Juvenile Blue Tangs, Acanthurus coeruleus

We studied territoriality and habitat use by yellow phase juvenile blue tangs, Acanthurus coeruleus, on a small fringing reef in Barbados, West Indies. Juvenile blue tangs occurred on the reef crest, spurs, and a transition zone between the reef crest and reef flat at a density of about 8 individuals per 100 m2, but were much rarer on the reef flat. They were solitary and occupied stable home ranges (median=0.85 m2) that increased with body size. Observational and experimental data documented aggressive defense of home ranges against conspecific and to a lesser extent congeneric, A. bahianus, juveniles (about 7.5 approaches and attacks per hour directed at intruders). Home range locations were structurally more complex and closer to a vertical face than expected by chance. Although juvenile blue tang territories overlapped considerably with those of larger and more aggressive Stegastes damselfish, which are believed to exclude solitary adult Acanthurus spp. from reef crest and spurs, the tangs avoided Stegastes and were rarely chased (<0.3 fleeing events per hour). Space use and social organization of yellow juvenile blue tangs contrast strikingly with that of both conspecific adults and congeneric juveniles.

Movements of Fishes Within and Among Fringing Coral Reefs in Barbados

Movement of coral reef fishes across marine reserve boundaries subsequent to their initial settlement from the plankton will affect the ability of no-take reserves to conserve stocks and to benefit adjacent fisheries. However, the mobility of most exploited reef species is poorly known. We tagged 1443 individuals of 35 reef fish species captured in Antillean fish traps in the Barbados Marine Reserve and adjacent non-reserve over a two-month period. Trapping and visual surveys were used to monitor the movements of these fish during the trapping period and the subsequent two months. Estimates of distances moved were corrected for the spatial distribution of sampling effort and for the number of recaptures of individual fish. Recapture rates for individual species ranged from 0–100% (median=38%). Species mobility estimated by recapture and resighting were highly correlated. Most species were strongly site attached, with the majority of recaptures and resightings occurring at the site of tagging. However, only one of 59 tagged jacks (Caranx latus, C. ruber) was ever resighted, suggesting emigration from the study area. All species were occasionally recorded away from the sites where they had been tagged (20–500 m), and several species, including surgeonfish, Acanthurus bahianus, A. coeruleus, filefish, Cantherhines pullus, butterflyfish, Chaetodon striatus, angelfish Holocanthus tricolor and parrotfish, Sparisoma viride, ranged widely within reefs. In contrast, few movements were observed between reefs separated by more than 20 m of sand and rubble, and no emigration from the Reserve was recorded. Most reef fishes vulnerable to Antillean traps appear sufficiently site-attached to benefit from reserves. However, many species move over a wide enough area to take them out of small reserves on continuous reef. Use of natural home range boundaries could minimize exposure of fishes in reserves to mortality from adjacent fisheries.

Habitat/sex differences in time at cleaning stations and ectoparasite loads in a Caribbean reef fish

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 193:191-199 (2000) - doi:10.3354/meps193191 Habitat/sex differences in time at cleaning stations and ectoparasite loads in a Caribbean reef fish Paul C. Sikkel1,2,*, Claire A. Fuller2, Wayne Hunte1 1Bellairs Research Institute of McGill University, St. James, Barbados, West Indies 2Department of Biology, Blackburn Hall 334, Murray State University, Murray, Kentucky 42071-0009, USA *E-mail: paul.sikkel@murraystate.edu ABSTRACT: We compared time spent at cleaning stations and ectoparasite loads for adult and sub-adult yellowtail damselfish Microspathodon chrysurus on nearshore fringing reefs in Barbados. In a preliminary study on 2 reefs in summer 1997, both time spent at cleaning stations and frequency of chafing were inversely correlated with distance from shore. A subsequent study in spring 1998 of fish at the shore- and seaward ends of 8 reefs revealed a strong sex by habitat association, with males predominating at the seaward end and females predominating at the shore end. Females and combined fish at the shore end of reefs had access to fewer cleaners but spent more time visiting cleaners than males and combined fish at the seaward end of reefs. Chafing showed the same relative difference but was not significant. Ectoparasites included gnathiid isopod larvae, parasitic copepods, and dactylogyrid monogeneans. Total crustacean loads, but not monogenean loads, increased with body size. With the effects of body size statistically removed, crustacean loads were significantly higher in females and fish at the shore end of reefs. Monogeneans showed a similar but marginally non-significant trend. These data indicate an association between ectoparasite loads and amount of time spent at cleaners, and thus appear consistent with adaptive, mutualistic hypotheses of client-cleaner interactions. However, the causal relationships between them, habitat, and sex remain to be determined. KEY WORDS: Pomacentridae · Coral reef fish · Ectoparasites · Cleaning symbiosis · Caribbean · Copepoda · Monogenea · Gnathiidae Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 193. Publication date: February 28, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.

Variable larval growth in a coral reef fish

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 206:213-226 (2000) - doi:10.3354/meps206213 Variable larval growth in a coral reef fish Steven P. Searcy*, Su Sponaugle** Marine Sciences Research Center, State University of New York at Stony Brook, Stony Brook, New York 11794-5000, USA Present addresses: *Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA. E-mail: spsearcy@unity.ncsu.edu **Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Florida, Miami 33149-1098, USA ABSTRACT: Understanding the functional linkages between the pelagic and demersal stages of marine organisms is a central goal in ecology. To better understand events that occurred during the larval period as well as their initial influence on juvenile traits, we examined individual level variation in early life-history traits (larval and early juvenile otolith growth rates, size-at-age, and larval duration) of 3 seasonal cohorts of the common coral reef fish Thalassoma bifasciatum (Bloch) (Labridae). Juveniles were collected at regular intervals (every second day) for 2 wk following their first appearance on the nearshore reefs of Barbados, West Indies. Otolith analysis indicated that each cohort exhibited a broad range of larval traits. Individuals with shorter larval durations had faster otolith growth and settled at relatively smaller sizes (based on otolith length and standard length) than larvae with longer larval durations, which exhibited slower otolith growth rates. Despite the range in larval durations for T. bifasciatum, otolith growth records revealed no evidence for delay of metamorphosis. Instead, the range in larval durations is likely to be the result of a variable pelagic environment influencing growth rates. Because metamorphosis in this species is an energetically costly non-feeding (3 to 5 d) period, we propose that successful metamorphosis requires a minimum energy reserve. Slower growers may need to remain in the plankton longer (consequently attaining larger sizes) to obtain this minimum condition. Variability in early life-history traits also occurred among the seasonal cohorts. Despite differences in patterns of larval otolith growth, mean larval duration was similar for the 2 fall cohorts (57 and 55 d), but much shorter for the spring cohort (42 d). Such inter-cohort variability in early life-history traits suggests a variable pelagic environment. In contrast to the larval period, juvenile growth rates were much less variable within and among cohorts, reflecting a more constant physical and biological environment on the reef. KEY WORDS: Coral reef fish · Early life-history traits · Juvenile growth · Larval growth · Growth plasticity · Otolith · Pelagic larval duration · Condition at settlement · Thalassoma bifasciatum Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 206. Online publication date: November 03, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.