Fish Spawning Aggregations Research Articles

Seasonal, annual, and long-term trends in commercial fisheries for aggregating reef fishes in the Gulf of California, Mexico

In order to assess the contribution of fish spawning aggregations and aggregating species to commercial marine fisheries in the Gulf of California, we: (1) investigated associations between the timing of spawning aggregations and monthly trends in commercial landings and ex-vessel revenues for aggregating reef fishes in the southwest Gulf of California and (2) compared present (2000–2005) and past (1956–1961) landings of aggregating species groups from the entire Gulf. Species known to form seasonal spawning aggregations comprised the eight most important commercial reef fish fisheries of the southwest Gulf with respect to landings and ex-vessel revenues, and three of these species increased in annual landings between 1999 and 2007. Peaks in mean monthly landings and revenues for five of eight aggregating species coincided with the timing of their spawning aggregations, whereas commercial fisheries for the remaining three species did not specifically target spawning aggregation periods. Comparisons of past and present landings showed an expansion of targeted species groups, increased landings for most aggregating species groups, and declines in the landings of several large-bodied species groups. Our results suggest that targeted management of spawning aggregations is needed for some but not all species, assessments on the interaction between fisheries and spawning aggregations are needed for most species, and restrictions on certain gear types are necessary to create sustainable fisheries for aggregating fishes in the Gulf.

Sea bottom geomorphology of multi-species spawning aggregation sites in Belize

Large, commercially important coral reef fishes such as Nassau grouper Epinephelus striatus are known to spawn at specific places and times in a so-called transient fish spawning aggre- gation (FSA). Traditional E. striatus spawning sites also serve as multi-species FSA sites. Many sites have been extirpated by overfishing or have shown dramatic declines. The objectives of this paper are to: (1) characterize the sea bottom geomorphology of all known transient FSA sites in Belize; (2) provide an evaluation of the multi-species aspects of known FSA sites; and (3) evaluate a prediction of 2 potential FSA sites based on the relationship between seafloor characteristics and fish aggrega- tions. The reef structures surrounding FSA sites were defined in relation to their depth and proxim- ity to shelf edges, deep water, reef channels, and reef promontory tips. All (n = 14) transient FSAs occurred at convex-shaped reef structures jutting out over steep walls into deep water. All FSA sites were located <100 m from shelf edges and <200 m from reef promontory tips, and at a mean of 78 ± 62 m from 100 m depth. Geomorphologically distinctive features at known FSAs allowed us to iden- tify 2 new multi-species FSA sites exhibiting similar characteristics. All the primary FSA sites in Belize are reef promontories, but the reasons why fish aggregate at these sites remain unclear.

Spatial and temporal use of spawning aggregation sites by the tropical sciaenid Protonibea diacanthus

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 403:193-203 (2010) - DOI: https://doi.org/10.3354/meps08469 Spatial and temporal use of spawning aggregation sites by the tropical sciaenid Protonibea diacanthus Jayson M. Semmens1,*, C. D. Buxton1, E. Forbes1, M. J. Phelan2,3 1Marine Research Laboratory, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 49, Hobart, Tasmania 7001, Australia 2Department of Primary Industries, Fisheries and Mines, GPO Box 3000, Darwin, Northern Territory 0801, Australia 3Present address: Tourism and Visitor Services, Environmental Protection Agency, Whitsunday Office, PO Box 332, Airlie Beach, Queensland 4802, Australia *Email: jayson.semmens@utas.edu.au ABSTRACT: Fish spawning aggregations (FSA) are generally spatially and temporally predictable, making them particularly vulnerable to fishing, which is capable of rapidly removing a significant proportion of the aggregated adults and reducing egg production. These effects may cause the loss of the aggregation altogether. In the Northern Territory (NT), Australia, repeated fishing of known aggregations of the tropical sciaenid species, the blackspotted croaker Protonibea diacanthus, is probably unsustainable, particularly given this species’ decline elsewhere. Acoustic monitoring was used to examine the temporal and spatial movement patterns and site fidelity of P. diacanthus in the NT. Fish were only detected at their respective aggregations, providing no evidence of large-scale movements between FSA. There was evidence for behavioural polymorphism in the aggregations, and fish monitored for ≥1 yr showed decreased presence during cooler months and increased presence during warmer months when peak spawning occurs. The tidal cycle significantly influenced the detection of tagged fish, with detections peaking on running tides, the peak period for catching P. diacanthus, suggesting that this is when they feed. This study has provided important information on the connectivity and dynamics of P. diacanthus aggregations in the NT, including crucial information for implementing appropriate management strategies for this vulnerable species. There appears to be little interchange of adult P. diacanthus at the spatial scale examined, which suggests that the separate FSA examined support separate adult populations. The presence of seemingly separate spawning populations of P. diacanthus has significant implications for their management, with the potential for each aggregation to be vulnerable to localised depletion. KEY WORDS: Spawning aggregation · Site fidelity · Acoustic monitoring · Sciaenidae · Fisheries management · Movement · Tidal cycle Full text in pdf format PreviousNextCite this article as: Semmens JM, Buxton CD, Forbes E, Phelan MJ (2010) Spatial and temporal use of spawning aggregation sites by the tropical sciaenid Protonibea diacanthus. Mar Ecol Prog Ser 403:193-203. https://doi.org/10.3354/meps08469 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 403. Online publication date: March 22, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

Observations of a Black Grouper (Mycteroperca bonaci) Spawning Aggregation in Bermuda

Diving observations at a black grouper (Mycteroperca bonaci) spawning aggregation site on Bermuda’s reef platform revealed many similarities to observations of this species obtained at multi-species spawning aggregation sites in Belize. In addition to similarities in body sizes, color patterns and some behavior, the principal spawning period in the days after the full moon was also similar. Although spawning was not observed in this study, there was ample indirect evidence of spawning at the site, i.e. courtship behavior by males, females with distended abdomens, and color changes. The formation of temporary spawning territories by males and courtship behavior within these territories is described and illustrated. Taken together, these data appear to indicate that the behavior of black grouper at spawning aggregations is consistent across a broad latitudinal range from Belize in the south to the northern limit of the species’ range in Bermuda. IntroductIon Relatively few studies have been published on the biology of black grouper (Mycteroperca bonaci), and most of these studies have concentrated on the reproductive biology of this protogynous hermaphroditic species (Crabtree and Bullock 1998, Garcia–Cagide et al. 2001, Brule et al. 2003, Teixeira et al. 2004). Spawning seasonality of black grouper at spawning aggregation sites in Cuba has been described by Claro and Lindeman (2003). Although the black grouper is recognized as a transient aggregation spawner (Domeier and Colin 1997), only a small number of studies have described the behavior of this species at fish spawning aggregation sites (FSAS) with the majority of the research being conducted in Belize (Heyman and Kjerve 2008, Paz and Sedberry 2008). One study in Florida (Eklund et al. 2000) examined an aggregation site in relation to a Marine Protected Area (MPA) boundary but provided less behavioral information as spawning was not observed. Whaylen et al. (2004) reported seeing small groups of black grouper with distended abdomens during observations at a primary Nassau grouper (Epinephelus striatus) spawning aggregation site in Little Cayman but spawning was not observed. Black grouper have been an important species to the Bermuda fishery for decades but suffered a significant decline in landings from the mid–1970s along with many other grouper species (Luckhurst 1996). Although it was known that black grouper aggregated to spawn, the location of spawning sites was apparently not well known in the local fishing industry. In contrast, red hind (Epinephelus guttatus) spawning aggregation sites were well–known and heavily fished, which prompted early management action to seasonally protect these sites (Luckhurst 1998, Luckhurst and Trott 2009). In the summer of 2003, the location of a spawning aggregation site for black grouper was revealed by fishermen and this lead to research to define the dynamics of the aggregation. It was determined that the black grouper site was relatively close to an existing red hind site which was seasonally closed to all fishing. Anecdotal evidence indicated that the black grouper site was being heavily fished and that the bag limit of one fish per boat per day was being routinely exceeded. As enforcement of the bag limit was problematic due to the large number of landing sites, it was decided to incorporate the black grouper site into a redefined and enlarged seasonally protected area (Fisheries Protected Areas Order 2004) which included the original red hind spawning aggregation site (Luckhurst, pers. obs.). Only after the site was seasonally closed to fishing was it possible to conduct an intensive research program to study the aggregation and learn more about its dynamics without interaction with fishermen at the site. The data presented here are the first to be derived from this ongoing study. MAterIAls And Methods A week before diving observations began, 2 mooring buoys were placed about 40 m apart near the presumed center of the spawning aggregation site at a depth of about 30 m. This was done to avoid anchoring on the site which could have disturbed the aggregated fish and also increased the efficiency of boat operations. There were 2 dive boats on the site for 3 days of the project with a single boat on the remaining 2 days. Diving observations commenced on the day of the full moon in June 2005 and continued for 6 consecutive days. No diving was possible on the fifth day due to rough sea conditions at the site. Teams of divers from each boat (2–4 divers per team) recorded their observations on waterproof paper on slates and all of the daily observations made during the study were collated and used for the present analysis. Divers surveyed the area widely and made estimate counts of the number of fish within their view and also estimated fish sizes. In addition, divers made notes on behavior and color patterns. After each dive, team members discussed

Geomorphometric Patterns of Nassau Grouper (Epinephelus striatus) Spawning Aggregation Sites in the Cayman Islands

Reef fish spawning aggregation sites are essential life habitats vulnerable to exploitation by fishermen, yet no quantitative comparisons of sites exist to understand their geomorphologic patterns. The objective of this study was to evaluate the geospatial aspects of known Nassau grouper spawning aggregation sites in the Cayman Islands. The results illustrate that the five known Nassau grouper spawning aggregation sites are located at convex-shaped reefs within 1 km of reef promontory tips. Further, all sites are found in 25–45 m depth, less than 50 m from shelf edges. Finally, they have been documented as multi-species spawning aggregation sites.

Historical and contemporary evidence of a mutton snapper (Lutjanus analis Cuvier, 1828) spawning aggregation fishery in decline

Scientific information on reef fish spawning aggregation fisheries is sparse in light of numerous regional declines and extirpations from overexploitation. Fisher interviews of the small-scale commercial mutton snapper (Lutjanus analis) spawning aggregation fishery at Gladden Spit, Belize, suggests a historic decadal decline. The reported trend is supported by analysis of inter-seasonal catch and effort and yield (2000–2002) that reveals a 59% decline in catch per unit effort (CPUE) and a 22% decrease in mean landings per boat. Declining population-level trends are also supported by a significant decrease in inter-annual median lengths of mutton snappers (2000–2006). These findings demonstrate the need for additional life history information that includes length-associated age and details on growth to provide clearer support of the effects on, and responses by, populations following fishing. In view of the historical changes to mutton snapper CPUE and landings at Gladden Spit and the fishery-associated declines in fish spawning aggregations observed globally, a precautionary approach to spawning aggregation management is warranted that provides full protection from fishing to enhance population persistence. The findings also highlight the need for substantially greater enforcement and long-term fisheries monitoring under a comprehensive regional management strategy.

Low-Cost Bathymetric Mapping for Tropical Marine Conservation—A Focus on Reef Fish Spawning Aggregation Sites

Marine conservation scientists and managers working in the tropics need bathymetric data, yet there exists no relatively simple and inexpensive system to derive them. We designed a system to produce bathymetric maps in 0–1,000 m water depth in less time, with less cost, and with less effort than any other system available. The system uses Landsat TM imagery to guide the collection and visualization of depth soundings obtained with a commercially available fish finder/GPS on a small boat. ArcGIS is used for interpolation and data display. The system was used to map two reef fish spawning aggregation sites in Belize and may be useful for shelf-edge mapping in other tropical locations.

Predator-prey relations at a spawning aggregation site of 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 203:275-288 (2000) - doi:10.3354/meps203275 Predator-prey relations at a spawning aggregation site of coral reef fishes Gorka Sancho1,*, Christopher W. Petersen2, Phillip S. Lobel3 1Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA 2College of the Atlantic, 105 Eden St., Bar Harbor, Maine 04609, USA 3Boston University Marine Program, Woods Hole, Massachusetts 02543, USA *Present address: AZTI-Technological Institute for Fisheries and Food, Txatxarramendi Ugartea z/g, 48395 Sukarrieta, Spain. E-mail: gsancho@whoi.edu ABSTRACT: Predation is a selective force hypothesized to influence the spawning behavior of coral reef fishes. This study describes and quantifies the predatory activities of 2 piscivorous (Caranx melampygus and Aphareus furca) and 2 planktivorous (Melichthys niger and M. vidua) fishes at a coral reef fish-spawning aggregation site in Johnston Atoll (Central Pacific). To characterize predator-prey relations, the spawning behavior of prey species was quantified simultaneously with measurements of predatory activity, current speed and substrate topography. The activity patterns of piscivores was typical of neritic, daylight-active fish. Measured both as abundance and attack rates, predatory activity was highest during the daytime, decreased during the late afternoon, and reached a minimum at dusk. The highest diversity of spawning prey species occurred at dusk, when piscivores were least abundant and overall abundance of prey fishes was lowest. The abundance and predatory activity of the jack C. melampygus were positively correlated with the abundance of spawning prey, and therefore this predator was considered to have a flexible prey-dependent activity pattern. By contrast, the abundance and activity of the snapper A. furca were generally not correlated with changes in abundance of spawning fishes. Spawning prey fishes were more common over substrates with complex topography, where refuges from piscivores were abundant. Piscivores differentially selected group-spawning species during spawning rushes over pair-spawning and non-spawning fishes. Overall attack rates by piscivores on adult spawning fishes were higher than by planktivores feeding on recently released eggs. The triggerfishes M. niger and M. vidua fed most actively at dusk and selected as prey those species of reef fishes that produced eggs of large size. KEY WORDS: Predator-prey interactions · Predation · Piscivory · Planktivory · Spawning · Coral reef fishes Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 203. Online publication date: September 18, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.