Spawning Aggregations Research Articles

ROV Observations on Reproduction by Deep-Sea Cephalopods in the Central Pacific Ocean

Telepresence-enabled operations by remotely operated vehicles (ROVs) allow many researchers a unique perspective on morphology, behavior, and small-scale distributions of deep-sea animals. I present some examples of cephalopod natural history from recent ROV dives in the central Pacific Ocean. These examples include clues to reproductive behavior of deep-sea squids and cirrate “dumbo” octopods. During 7-12 March 2017, the ROV Deep Discoverer (D2) operating from NOAA Ship Okeanos Explorer recorded high-definition video of several squid in the genus Chiroteuthis. These included a mature male, a mature female, and a moribund squid identifiable as C. picteti. The female had obviously mated, with spermatangia implanted in many locations, and was holding in its arms another squid that appeared to be another Chiroteuthis. Considered together, these observations may indicate a deep-sea spawning aggregation and, possibly, sexual cannibalism. Another series of observations by D2 revealed eggs of cirrate octopods attached to octocorals. The remarkable thing about these observations was that in two of them (18 March and 4 May) the egg chorion had swollen and burst the external egg capsule. This may explain how the hatching embryo is able to escape from the tough protective coating secreted by the oviducal gland of cirrates but not secreted by the better-known incirrate octopods.

Are Atlantic goliath grouper, Epinephelus itajara, establishing more northerly spawning sites? Evidence from the northeast Gulf of Mexico

Many fish migrate long distances to form spawning aggregations—important life history events that reflect population reproductive potential—often at predictable times and places. However, we often do not know where and when aggregations form, or if they are characteristically similar across spatial gradients. For Atlantic goliath grouper, Epinephelus itajara (Lichtenstein, 1822), spawning aggregations have been verified from subtropical sites off the southeast and southwest coasts of Florida, and off the southern coast of Brazil. Here, we verify a spawning aggregation off the northwest Florida coast in warm temperate waters of the Gulf of Mexico and characterize the aggregation relative to those in south Florida. Evidence of a spawning aggregation was derived from seasonal differences in gamete stages, nocturnal sound production, and relative abundance on the presumed aggregation site. These patterns all paralleled those of south Florida spawning aggregations, but with a shorter spawning season. In northwest Florida, there was a spatiotemporal relationship with reproductive timing and surface water temperature, and with wind speed/water current direction, which indicate that timing of goliath grouper reproduction is optimal for larval transport and survival. This northwest Florida spawning aggregation is significant because it represents an expansion of approximately 3° farther north than previously verified aggregations.

Does a spatiotemporal closure to fishing Chrysophrys auratus (Sparidae) spawning aggregations also protect individuals during migration?

Understanding migration dynamics of fishes that aggregate-spawn is critical if spatiotemporal closures to fishing are expected to protect them. Concern over fishing of Chrysophrys auratus spawning aggregations in embayments near a west Australian city led to an annual 4-month spatial fishing closure. However, the extent to which it protects fish migrating to and from aggregations is unclear. Acoustic telemetry demonstrated a bimodal pattern of entry to and departure from the main embayment via only one of several pathways. Among years, 33%–56% of fish occurred in the pathway prior to the closure, but most left before it ceased. Fish were detected within the closure in multiple but not always consecutive years. Variation in migration timing and aggregation philopatry may alter capture risk, but pre- and postspawning migratory fish are fished in the main pathway and adjacent reefs, which would presumably impact spawning aggregation biomass. Assessment of this would assist in understanding whether expansion of the closure’s spatial and temporal limits is necessary to ensure spawning biomass or whether current management is sufficient.

Observation of a high abundance aggregation of the deep-sea urchin Chaetodiadema pallidum A. Agassiz and H.L. Clark, 1907 on the Northwestern Hawaiian Island Mokumanamana

AUV images of deep-sea megafauna on the seamount Mokumanamana in the Northwestern Hawaiian Islands revealed a large aggregation of the diadematoid urchin Chaetodiadema pallidum. This species had not been previously recorded on this seamount, but was known from other locations in the Hawaiian Archipelago. A total of 11,360 individuals were counted by eye from 1,369 seafloor images along the 200, 250, and 300 m depth contours on the west side of Mokumanamana. To estimate the full population size, Inverse Distance Weighting and Empirical Bayesian Kriging interpolation calculated a total population size of between 139,552 and 144,063 individuals. These estimates are 1-2 orders of magnitude greater than any previous estimates of urchin aggregation abundances. Little biological data exists for this species; thus, it is difficult to know if this is a spawning aggregation, a feeding front, a type of “schooling” behavior, or some combination thereof, but a food source did seem to be present in the form of mesophotic green algal detritus.

Intraspecific DNA contamination distorts subtle population structure in a marine fish: Decontamination of herring samples before restriction-site associated sequencing and its effects on population genetic statistics.

Wild specimens are often collected in challenging field conditions, where samples may be contaminated with the DNA of conspecific individuals. This contamination can result in false genotype calls, which are difficult to detect, but may also cause inaccurate estimates of heterozygosity, allele frequencies and genetic differentiation. Marine broadcast spawners are especially problematic, because population genetic differentiation is low and samples are often collected in bulk and sometimes from active spawning aggregations. Here, we used contaminated and clean Pacific herring (Clupea pallasi) samples to test (a) the efficacy of bleach decontamination, (b) the effect of decontamination on RAD genotypes and (c) the consequences of contaminated samples on population genetic analyses. We collected fin tissue samples from actively spawning (and thus contaminated) wild herring and nonspawning (uncontaminated) herring. Samples were soaked for 10min in bleach or left untreated, and extracted DNA was used to prepare DNA libraries using a restriction site-associated DNA (RAD) approach. Our results demonstrate that intraspecific DNA contamination affects patterns of individual and population variability, causes an excess of heterozygotes and biases estimates of population structure. Bleach decontamination was effective at removing intraspecific DNA contamination and compatible with RAD sequencing, producing high-quality sequences, reproducible genotypes and low levels of missing data. Although sperm contamination may be specific to broadcast spawners, intraspecific contamination of samples may be common and difficult to detect from high-throughput sequencing data and can impact downstream analyses.

Hypothesizing novel mating behaviours in the squaretail grouper based on direct behavioural observations

Historically unfished, high-density spawning aggregations are vanishingly uncommon. Behavioural observations from such aggregations are rare, and may be sometimes novel and unexpected. Given the weight of evidence required to document spawning aggregations, how can we best report rare and unusual behavioural variations in spawning populations? Based on two years of in-water observations of a high-density spawning aggregation of the squaretail grouper in the Lakshadweep Archipelago, we described a previously unreported male alternative reproductive tactic (ART) and an inverse size assortment with large males courting several small females that shoaled mid-water (https://doi.org/10.1186/s12898-017-0120-5). In critiquing our manuscript, it has been suggested that our observations, methodologies and interpretation are inadequate, flawed, and do not fit within currently accepted theory (https://doi.org/10.1186/s12898-018-0206-8). While offering a detailed counter of the main methodological and theoretical criticisms we question how best to document and interpret novel behaviours in poorly known systems. Reporting novelty itself can hardly be the basis of criticism. Our report relied on direct in-water observations, conducted at peak densities over two spawning years. The critique ignores this, choosing instead to focus on a supplementary video which was not the basis of our conclusions. Like other researchers working on this species, we did not directly observe mating, but report courtship as a well-established proxy used across mating systems studies. Apart from these methodological concerns, the authors suggest that there is no theoretical support for our observations. However, sexual selection theory provides well-established frameworks showing that, at very high mating densities, a variety of tactics can emerge, that often vary considerably between populations and locations. In our original paper, we use this broader theory of sexual selection together with detailed behavioural data to propose plausible evolutionary explanations that bear testing in these novel, high-density systems. We agree with the authors that novel observations should be scrutinised carefully as they can challenge our current understanding of the range of behaviours populations display and serve as a springboard for theoretical advancement. Given their rarity, these observations should be evaluated against the rigour of their documentation and the transparency of their reporting. In this context, we hope our carefully documented observations serve as a useful addition to the fascinating and complex natural history of species like the squaretail grouper.

Motion in the ocean-Paradigm shift in movement ecology requires "sedentary" organisms to be redefined.

In Focus: Hamel, J.-F., Sun, J., Gianasi, B. L., etal. (2019). Active buoyancy adjustment increases dispersal potential in benthic marine animals. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.12943 Effective ecosystem-based fisheries and conservation management relies on the accuracy of population structure and connectivity models. The majority of sedentary marine species are pelago-benthic, meaning the pelagic larval stages disperse using ocean currents, and the adults are stationary or crawl slowly over the seabed. Adult movement was, until recently, thought to be insignificant due to the limited spatial range. In this issue, a novel method of translocation for adults that may far exceed the dispersion capability of the juveniles is presented, providing evidence for important effects of adult dispersal. Active buoyancy adjustment (ABA) is a behavioural response to environmental stressors or water currents that enables echinoderm Asteroidea (sea stars) and Holothuroidea (sea cucumbers) to efficiently relocate. Adult relocation using tides could explain mass spawning aggregations that increase population and individual fitness, and less advantageous mass stranding events. Implications of ABA for future marine management and policy are discussed.

Adaptive genetic variation underlies biocomplexity of Atlantic Cod in the Gulf of Maine and on Georges Bank.

Atlantic cod (Gadus morhua) populations in the Gulf of Maine (GoM) are at a fraction of their historical abundance, creating economic hardships for fishermen and putting at risk the genetic diversity of the remaining populations. An understanding of the biocomplexity among GoM populations will allow for adaptive genetic diversity to be conserved to maximize the evolutionary potential and resilience of the fishery in a rapidly changing environment. We used restriction-site-associated DNA sequencing (RADseq) to characterize the population structure and adaptive genetic diversity of five spawning aggregations from the western GoM and Georges Bank. We also analyzed cod caught in the eastern GoM, an under-sampled area where spawning aggregations have been extirpated. Using 3,128 single nucleotide polymorphisms (SNPs), we confirmed the existence of three genetically separable spawning groups: (1) winter spawning cod from the western GoM, (2) spring spawning cod, also from the western GoM, and (3) Georges Bank cod. Non-spawning cod from the eastern GoM could not be decisively linked to either of the three spawning groups and may represent a unique component of the resource, a mixed sample, or cod from other unsampled source populations. The genetic differentiation among the three major spawning groups was primarily driven by loci putatively under selection, particularly loci in regions known to contain genomic inversions on linkage groups (LG) 7 and 12. These LGs have been found to be linked to thermal regime in cod across the Atlantic, and so it is possible that variation in timing of spawning in western GoM cod has resulted in temperature-driven adaptive divergence. This complex population structure and adaptive genetic differentiation could be crucial to ensuring the long-term productivity and resilience of the cod fishery, and so it should be considered in future management plans.

Visitation patterns of camouflage groupers Epinephelus polyphekadion at a spawning aggregation in Fakarava inferred by acoustic telemetry

Many species of groupers form transient fish spawning aggregations (FSAs) that are both spatially and temporally predictable, making them highly vulnerable to fishing. Consequently, many known aggregations have disappeared, making the collection of additional baseline data imperative to inform management actions and decisions that have the capacity to protect these important areas in the long term. Using acoustic telemetry and underwater observations, we document the spatio-temporal dynamics of the camouflage grouper Epinephelus polyphekadion at a FSA in Fakarava, French Polynesia. We show that grouper arrival at the aggregation site started 2 weeks before the full moon with a core area density that increased from 0.13 to 1.25 fish m -2 during the observation period. Following reproduction, almost all camouflage groupers left the FSA site within 48 h. Among 30 tagged groupers in 2011 and despite a relatively low receiver coverage in the pass, 30% returned to the FSA the following year confirming patterns of FSA site fidelity of the species found in previous studies at other locations. Our results confirm that the current management procedures protecting the FSA under the UNESCO biosphere reserve are critical in maintaining the functional role of the FSA by ensuring the persistence and sustainability of large and healthy populations of groupers and sharks.

Identifying the distribution of Atlantic cod spawning using multiple fixed and glider-mounted acoustic technologies

Abstract Effective fishery management measures to protect fish spawning aggregations require reliable information on the spatio-temporal distribution of spawning. Spawning closures have been part of a suite of fishery management actions to rebuild the Gulf of Maine stock of Atlantic cod (Gadus morhua), but difficulties remain with managing rebuilding. The objective of this study was to identify the spatial and temporal distribution of cod spawning during winter in Massachusetts Bay to improve our understanding of cod spawning dynamics and inform fisheries management. Spawning was investigated in collaboration with commercial fishermen during three winter spawning seasons (October 2013–March 2016) using acoustic telemetry and passive acoustic monitoring equipment deployed in fixed-station arrays and mounted on mobile autonomous gliders. Tagged cod exhibited spawning site fidelity and spawning primarily occurred from early November through January with a mid-December peak and some inter-annual variability. The spatial distribution of spawning was generally consistent among years with multiple hotspots in areas >50 m depth. Current closures encompass most of spawning, but important areas are recommended for potential modifications. Utilizing multiple complementary technologies and deployment strategies in collaboration with commercial fishermen enabled a comprehensive description of spawning and provides a valuable model for future studies.

Small-scale fishers' perceptions about the performance of seasonal closures in the commonwealth of Puerto Rico

The targeting of spawning aggregations is one of the most significant pressures facing coral reef ecosystems. The use of seasonal closures has been advanced for protecting aggregating fisheries for which managers have limited information on the location and timing of their reproductive events; however, few studies have examined the performance of these types of closures. This study assesses the perceptions of 150 fishers regarding the performance of seasonal closures in the Commonwealth of Puerto Rico.Our results show that most fishers perceived that seasonal closures are effective fishery management measures. Across the six seasonal closures examined, fishers reported that these closures protected spawning aggregations and, to a lesser degree, increased fish abundance. These measures, however, did not always improve fishers' livelihoods nor result in their support for the seasonal closures. The loss of resource and market access during periods of high consumer demand and overlapping seasonal closures were the main causes of financial distress.Fishers indicated that the performance of the seasonal closures could be improved by increasing investments in monitoring, control, and surveillance capabilities, and adjusting their timing to accommodate economic and local ecological considerations. Fishers argued that revisions were necessary because some species spawned year-round or outside closure windows. Some fishers also called for replacing seasonal closures with alternative management measures (e.g., area-time closures, marine protected areas, gear restrictions), conducting additional scientific research, and improving fisher education. This work underscores that beliefs about conservation and livelihood outcomes are closely linked to the quality of management, the importance of conducting periodic assessments, and engaging fishers in decision-making to increase accountability, transparency, and support for management interventions.

Propagation loss of spawning calls produced by spotted seatrout Cynoscion nebulosus and the effective detection area of passive acoustic sampling

Acoustic signaling in fish has been observed in conjunction with various behaviors but most commonly is associated with spawning. Sound production has been used to identify spawning sites for multiple species, but sound propagation characteristics are often not accounted for, severely limiting the spatial resolution at which spawning sites can be identified. We examined the propagation loss of seatrout calls in the very shallow environment of an estuary using recorded calls and an array of stationary hydrophones. We estimated the minimum expected source level of a seatrout call from the maximum recorded sound pressure level (SPL) of individual fish calls made in situ at spawning sites. Based on preliminary data from 86 samples, the minimum expected source level of an individual call is 142.1 ± 0.9 (CI95) dBrms re: 1 µPa at 1m. Measurements of propagation loss were fitted with a logarithmic model, and preliminary results showed that seatrout calls were detectable above background noise levels between 64 m and 512 m from the source. These results can be used to relate sound levels to the abundance of fish present at a spawning aggregation and enhance the precision of locating spawning sites using passive acoustics. Acoustic signaling in fish has been observed in conjunction with various behaviors but most commonly is associated with spawning. Sound production has been used to identify spawning sites for multiple species, but sound propagation characteristics are often not accounted for, severely limiting the spatial resolution at which spawning sites can be identified. We examined the propagation loss of seatrout calls in the very shallow environment of an estuary using recorded calls and an array of stationary hydrophones. We estimated the minimum expected source level of a seatrout call from the maximum recorded sound pressure level (SPL) of individual fish calls made in situ at spawning sites. Based on preliminary data from 86 samples, the minimum expected source level of an individual call is 142.1 ± 0.9 (CI95) dBrms re: 1 µPa at 1m. Measurements of propagation loss were fitted with a logarithmic model, and preliminary results showed that seatrout calls were detectable above background noise levels between 64 m ...

Potential connectivity between marine protected areas in the Mesoamerican Reef for two species of virtual fish larvae: Lutjanus analis and Epinephelus striatus

The potential connectivity network of marine protected areas (MPAs) with spawning aggregations sites in the Mesoamerican Barrier Reef system (MBRS) was examined through simulated dispersal of two study cases, Lutjanus analis and Epinephelus striatus larvae. The analysis was based on a particle tracking model incorporating four years of daily horizontal surface currents from the global scale HYCOM 1/12°. We carried out two approaches, the first one used the period of larval duration (PLD) and the second the time of flexion of the notochord as the limit time of dispersion of the particles. Additionally, peak spawning seasons (December-Febraury for E. striatus and March-July for L. analis), lunar phases and georeferenced spawning aggregations sites were considered for releasing the virtual larvae. Our findings suggest that in general, the network of MPAs of the MBRS are well connected, however, the connectivity network structure presented variations in the relative role of each MPA, and their played role will depend on the specie reproductive period, the oceanographic conditions and the assumed biological approximation (such as PLD or flexion). Our analysis suggested a regionalization of the MBRS. A southern region (Bacalar Chico, Roatan and Sapodilla) with low degree of connectivity, moderate self-recruitment rate, and low values of betweenness centrality. A second southern region (Turneff Island, Lighthouse Atoll, Glover Reef Atoll and Gladen Spit) with high rate of self-recruitment (up to 20%) that could be related to self-recruitment due to retention mechanism of the Honduras Gyre, with high values of source of larvae, function as bridges that connect the south zone with the north of the system. A third region (Mahahual and Xcalak) showing sink of larvae, low larval arrival rate but self-recruitment, low values of betweenness centrality area influenced by slow and variable currents and the presence of a southward flow. And a fourth region (Chinchorro, Sian Ka’an, Puerto Morelos and Cozumel) with moderate fast current speed (Yucatan Current), low self-recruitment, larval sink, bridge with the Gulf of Mexico and Florida.

Reproductive behaviour and concurrent sound production of Gulf grouper Mycteroperca jordani (Epinephelidae) at a spawning aggregation site.

The reproductive and acoustic behaviours of Gulf grouper Mycteroperca jordani were studied at a spawning aggregation site in the southern Gulf of California, México. In May 2015-2017, divers located and surveyed a spawning aggregation site within Cabo Pulmo National Park. Adult M. jordani conformed to a lek mating system in which large males formed territories over sand adjacent to a rocky reef that were spatially segregated from smaller females outside of courtship and spawning periods. Females moved into male territories during evening hours to spawn. Male courtship behaviours targeted a single female, included head shakes and burst rises and preceded pair spawning prior to sunset. Males and females displayed three shared colour phases, but four phases were sex-specific. During evening hours, courtship and spawning, both sexes exhibited sexual dichromatism concurrent with reproductive behaviours. The pair-spawning mating system and observations of bimodal size distributions by sex support previous claims of protogyny in the species. Males produced sounds during territorial patrols, courtship and spawning rushes, which corroborated the importance of acoustic communication within the behavioural repertoire associated with spawning. Long-term acoustic monitoring revealed increases in total sounds detected day-1 from March through June with diel increases (e.g., evenings) that may be indicative of the spawning season. Observations of spawning on 12 consecutive evenings in May 2017 coupled with extended periods of sound production suggest that spawning does not follow a lunar rhythm. This first description of the mating system and sounds of the endangered M. jordani facilitates future development of seasonal and areal protections to restore and manage the species.

Male Territory Swamping in a Lek-like Mating System Alters Courtship Success in a Fish Spawning Aggregation

Event Abstract Back to Event Male Territory Swamping in a Lek-like Mating System Alters Courtship Success in a Fish Spawning Aggregation Terry J. Donaldson1* 1 University of Guam Marine Laboratory, United States Many reef fish species that form spawning aggregations utilize a lek-like mating system in which males establish temporary courtship territories that they defend against rival males while attracting females to spawn. At a resident spawning aggregation site located at Finger Reef, Guam, male Cheilinus trilobatus (Labridae) holding territories along the outer edge of the site experience significantly greater courtship success compared with males holding territories within the site’s interior. Males holding edge territories are always successful in defending these territories from intruding males, even when they are engaged in courtship. Recently, however, increases in the number of males present at the spawning aggregation site have resulted in an increase in the number of territory intrusions during courtship periods. These intrusions “swamp” a normally successful male’s territory and make defense difficult. Multiple intruders not chased away or simply returning after being chased then court and spawn with females that arrive within the territory. Costs to the territory holder include lost courtship opportunities because of territorial interactions that interrupt courtship and reduced reproductive success because intruding males court successfully with females that visit the male’s territory and deprive him of the opportunity to do so. Acknowledgements None References None Keywords: Courtship, fish, Labridae, Reproduction, wrasse Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Oral Topic: ECOLOGY AND LIFE CYCLES Citation: Donaldson TJ (2019). Male Territory Swamping in a Lek-like Mating System Alters Courtship Success in a Fish Spawning Aggregation. Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00007 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Jun 2019; Published Online: 14 Aug 2019. * Correspondence: Prof. Terry J Donaldson, University of Guam Marine Laboratory, Guam, United States, tdonaldson@triton.uog.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Terry J Donaldson Google Terry J Donaldson Google Scholar Terry J Donaldson PubMed Terry J Donaldson Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Temporal stability and assignment power of adaptively divergent genomic regions between herring (Clupea harengus) seasonal spawning aggregations.

Atlantic herring (Clupea harengus), a vital ecosystem component and target of the largest Northwest Atlantic pelagic fishery, undergo seasonal spawning migrations that result in elusive sympatric population structure. Herring spawn mostly in fall or spring, and genomic differentiation was recently detected between these groups. Here we used a subset of this differentiation, 66 single nucleotide polymorphisms (SNPs) to analyze the temporal dynamics of this local adaptation and the applicability of SNP subsets in stock assessment. We showed remarkable temporal stability of genomic differentiation corresponding to spawning season, between samples taken a decade apart (2005 N = 90 vs. 2014 N = 71) in the Gulf of St. Lawrence, and new evidence of limited interbreeding between spawning components. We also examined an understudied and overexploited herring population in Bras d'Or lake (N = 97); using highly reduced SNP panels (N SNPs > 6), we verified little‐known sympatric spawning populations within this unique inland sea. These results describe consistent local adaptation, arising from asynchronous reproduction in a migratory and dynamic marine species. Our research demonstrates the efficiency and precision of SNP‐based assessments of sympatric subpopulations; and indeed, this temporally stable local adaptation underlines the importance of such fine‐scale management practices.

Assessing red drum spawning aggregations and abundance in the Eastern Gulf of Mexico: a multidisciplinary approach

Abstract Many marine fish form spawning aggregations (FSAs) and exhibit meta-population stock structure, affecting reproductive resilience and the optimal spatial scale of management. Red drum use a known FSA site off Tampa Bay (TB FSA site) and another presumed FSA site off Charlotte Harbor (CH FSA site). We studied these sites for 3 years (2012–2014) to assess space use and annual abundance at the TB FSA site using: (i) genetically profiled fish, non-lethally sampled by purse seine (n = 9087); (ii) aerial surveys (n = 37); and (iii) acoustic telemetry (n = 122 fish). Thousands of fish concentrated at the TB FSA site to spawn each year, dispersing afterward to an area of at least ∼150 km along the coast and 90 km offshore. Fish acoustically tagged at the TB FSA site showed strong annual spawning site fidelity (91% in 2013 and 85% in 2014) and the straying rate to the CH FSA site to the south was low (6–13%). Annual abundance at the TB FSA site varied, with the estimated abundance in 2013 being four times greater than that estimated for 2014. Similarly, aerial surveys in 2013 sighted 2.5 times as many aggregations as in 2014. However, fine-scale space use, which typically goes unassessed in abundance estimates (short-term surface behaviour and temporary migration), also differed between these years and needs to be integrated into future capture-mark–recapture models.

Comparison of catch, CPUE and length distribution of spawning aggregations of mutton snapper (Lutjanus analis) and grey triggerfish (Balistes capriscus) on a Mesoamerican coral reef

This study evaluates the habitat characteristics, fishing effort, and production, as well as changes in the individuals, such as changes in size frequency, of the spawning aggregations of mutton snapper Lutjanus analis and grey triggerfish Balistes capriscus , caught in the Chinchorro Bank Biosphere Reserve (CBBR), Mexico. The mutton snapper aggregation was located in coral patches, while the spawning aggregation of grey triggerfish was located on the windward terrace of the reef flat. Fishery data was obtained for the duration of the spawning event in 2008, with a total of 5 days for mutton snapper and 4 days for grey triggerfish. The fishery recorded a total of 830 mutton snappers, with individual sizes ranging from 40 to 77 cm in fork length (FL). Individual size and catch per unit effort (CPUE) decreased through time, with the lowest values presented at the end of the 5 days. In contrast, a total of 665 grey triggerfish were recorded in the catch, ranging from 45 to 61 cm (FL) with the largest sizes caught at the end of the fishing period, concurrently with the lowest CPUE. A lack of governance allowed both species to be harvested during their spawning aggregations. The creation of an international body composed of fishers, managers, conservationists, and scientists from the countries belonging to the Mesoamerican Reef System is urgently required to look for agreements in conservation and management strategies of these commercially important species.

Biophysical connectivity of snapper spawning aggregations and marine protected area management alternatives in Cuba

AbstractThe ability of larvae to move beyond the spatial range of adult migrations can be critical to the resilience of populations that aggregate to spawn. We reviewed the literature and unpublished information on larval transport modeling, reef fish spawning aggregations, and marine protected area (MPA) management to identify alternatives for Cuban spawning site conservation. Larval transport information is available at annual and decadal scales for eight Cuban sites for five species of snappers. Connectivity patterns were examined: (a) within Cuban regions, (b) among Cuban regions, and (c) among other countries. We compared this information with the distribution of protected areas relative to spawning sites, site management attributes, and potential alternatives. Of eight focal spawning sites, seven are in protected areas and one is proposed. Southeast and north‐central Cuba had highest estimated within‐region retention levels. Southwest and northwest sites exported relatively more larvae out‐of‐region. Southern regions produced larvae that reached Jamaica, the Cayman Islands and Haiti. All northern regions can export larvae to the southern Bahamas. The regions and sites within are geomorphologically diverse with variable fishing and socio‐economic attributes. Information on stock status and protected area efficacy is limited and field assessments of aggregation status are needed for multispecies spawning sites. Few management plans address spawning conservation or network connectivity opportunities for MPAs. An alternative is development of one or more regional workgroups of protected area specialists, fishery scientists, expert fishers, and other stakeholders. Temporal closures of fisheries before and during spawning season could also amplify effectiveness of current gear‐ and zoning‐based management tools.

Prioritizing monitoring and conservation efforts for fish spawning aggregations in the U.S. Gulf of Mexico

In the U.S. Gulf of Mexico (U.S. GOM), the identification and characterization of transient fish spawning aggregation (FSA) sites is recognized as a regional priority for conservation, but progress is hindered by a lack of understanding of FSA distributions for most exploited species. We employed information compiled in regional databases on FSAs and monitoring for the U.S. GOM to fit species distribution models and produce maps showing the areas likely to host single- and multi-species transient FSA sites. Our results revealed two distinct regions of the U.S. GOM for prioritizing monitoring and conservation efforts for transient FSAs: the coastal waters surrounding major bay systems, particularly those of Texas and Louisiana, and portions of the continental shelf edge (the Flower Garden Banks area and the West Florida shelf edge). The next step would be to locate and characterize actual transient FSA sites in the U.S. GOM by surveying within the areas we identified.