Fish

The Saba Bank is the largest submerged carbonate platform of 2,200 km2 in the Caribbean Sea, which lies partially within the Exclusive Economic Zone of the Netherlands and partially within the territorial waters of Saba and St. Eustatius. The Saba Bank houses an expansive coral reef ecosystem with a rich diversity of species and as such is also an important source of commercial fish for the nearby islands.

The Saba Bank furthermore forms the largest protected area of the Kingdom of the Netherlands, after the Dutch part of the Wadden Sea in Europe. It was declared a protected area by the Dutch Government in 2010 and has been registered as such in the Specially Protected Areas and Wildlife (SPAW) protocol of the Cartagena Convention for the Protection and Development of the Marine Environment of the Wider Caribbean. In 2012 it was internationally declared a Particularly Sensitive Sea Area (PSSA) by the International Maritime Organization (IMO) and an Ecological or Biological Significant Area (EBSA) by the Convention on Biological Diversity (CBD). As there are no large land masses nearby, the Saba Bank can be considered as relatively pristine and remote from human influences. Anthropogenic threats such as fisheries and environmental threats such as climate change, sea surface temperature increase and acidification, however, also threaten the Bank’s coral reefs.

As part of the Saba Bank research program 2011-2016, commissioned by the Dutch Ministry of Economic Affairs (EZ), expeditions to the Saba Bank were conducted in October 2011 and from 19 to 26 October 2013. The Saba Bank research program aims to obtain information on the biodiversity, ecological functioning and carrying capacity for commercial fisheries to facilitate sustainable management of the area. The expedition was funded by the Dutch Ministry of Economic Affairs and the World Wildlife Fund in the Netherlands.

The primary objectives of the 2011 and 2013 research expeditions were to collect data on benthic and reef fish communities, and on sponges and nutritional sources of the sponge community. Studies added to the 2013 expedition were research into the structural complexity of the reef; coral-algal interactions; and connectivity between populations. An international, multidisciplinary team of marine biologists investigated the coral reef structure as well as the spatial variation in species assemblages and population genetic connectivity of corals, algae, fish and sponges during eleven SCUBA dives at 20-30m depth.

During the expedition thirty-three 50m long transects resulted in more than 2000 images of the reef, and over 5000 fish counts of almost 100 fish species. A preliminary comparison with the data from 2011 gives the impression of a reduction in snappers, groupers and grunts, while there were noticeably more sharks. There were fewer algae on the Saba Bank than in 2011, possibly indicating a healthier reef, although there appeared to be a gradient of increasing algal cover towards the island of Saba. It seems unlikely that this is related to anthropogenic activities on the island, but more likely to natural causes.

An overview of collected data and preliminary results is given in this progress report. Further comparative analysis between the data collected in the 2011 and 2013 and further analysis between research components, e.g. between algal biomass, herbivorous fish biomass and nutrient levels, will be performed in 2014. This may give more information on the potential causes of the observed south-north algal gradient.

The expedition elicited large public interest and media coverage in both Dutch and Caribbean media (details provided in Appendix F). The work of the researchers, both above and under water, was also recorded on film as part of the documentary series Marine Life for Discovery Channel.

Abstract:

The South American species with the vernacular name "mollies" are analyzed and three new species of the genus Poecilia are described and figured, viz., P. boesemani n. sp. from Trinidad, P. koperi n. sp. from Venezuela and Colombia, and P. wandae n. sp. from Lake Maracaibo. Thirteen species of Poecilia are presently recognized from the northeastern part of South America and adjacent islands, viz., six mollies (including P. vivipara and P. caucana), five micropoeciliids, P. heterandria and the guppy (P. reticulata). Two different populations in both P. koperi and P. wandae are recognized, based on variation in pigmentation. From the type series of P. dovii Günther, 1866 and P. vandepolli Van Lidth de Jeude, 1887 lectotypes are selected. Four subspecies of P. gillii are defined as morphologically distinct and geographically correlated populations.

Poecilia reticulata, P. heterandria, and the micropoeciliids P. bifurca, P. parae, P. picta, P. branneri and P. minima are not considered, whereas P. laurae remains a species inquirendae. A geocline in characters of the species of Poecilia is recorded and a possible evolution is discussed. 

Abstract:

Based on a field survey and review of published records, I report the occurrence of 13 species of fishes in fresh waters of Curaçao. Seven species are new or previously unpublished freshwater records for the island. New records are also provided for the adjacent islands of Aruba and Bonaire. Although the native freshwater fish fauna is dominated by predatory gobiid and eleotrid fishes, the most frequently encountered species was the endemic molly, Poecilia vandepolli. The next most frequent species was the native mountain mullet (Agonostomus monticola), followed by the exotic Mozambique tilapia (Oreochromis mossambicus) and the native emerald sleeper (Erotelis smaragdus). High dams block surface water flows in Curaçao and prevent migration of native amphidromous fish. The introduced tilapia has apparently reduced the abundance of native species. 

Abstract:

Marine spatial population dynamics are often addressed with a focus on larval dispersal, without taking into account movement behavior of individuals in later life stages. Processes occurring during demersal life stages may also drive spatial population dynamics if habitat quality is perceived differently by animals belonging to different life stages. In this study, we used a dual approach to understand how stage-structured habitat use and dispersal ability of adults shape the population of a marine fish species. Our study area and focal species provided us with the unique opportunity to study a closed island population. A spatial simulation model was used to estimate dispersal distances along a coral reef that surrounds the island, while contributions of different nursery bays were determined based on otolith stable isotope signatures of adult reef fish. The model showed that adult dispersal away from reef areas near nursery bays is limited. The results further show that different bays contributed unequally to the adult population on the coral reef, with productivity of juveniles in bay nursery habitat determining the degree of mixing among local populations on the reef and with one highly productive area contributing most to the island’s reef fish population. The contribution of the coral reef as a nursery habitat was minimal, even though it had a much larger surface area. These findings indicate that the geographic distribution of nursery areas and their productivity are important drivers for the spatial distribution patterns of adults on coral reefs. We suggest that limited dispersal of adults on reefs can lead to a source–sink structure in the adult stage, where reefs close to nurseries replenish more isolated reef areas. Understanding these spatial population dynamics of the demersal phase of marine animals is of major importance for the design and placement of marine reserves, as nursery areas contribute differently to maintain adult populations.

Abstract:

The Saba Bank is a large submerged carbonate platform of approximately 2,200 km2 in the Caribbean Sea which lies partially within the Exclusive Economic Zone of the Netherlands and partially within the territorial waters of Saba and St. Eustatius. It was declared a protected area by the Dutch Government on 15 December 2010 and has been registered as such in the Specially Protected Areas and Wildlife (SPAW) protocol of the Cartagena Convention for the Protection and Development of the Marine Environment of the Wider Caribbean. Applications for a Particularly Sensitive Sea Area (PSSA) at IMO and Ecological or Biological Significant Area (EBSA) at CBD are pending.

As part of the Saba Bank research program 2011-2016, commissioned by the Dutch Ministry of Economic Affairs (EZ), an expedition to the Saba Bank was conducted from 22 to 29 October 2011. The Saba Bank research program aims to obtain information on the biodiversity, key ecological processes and carrying capacity for commercial fisheries to facilitate sustainable management of the area. The primary objectives of the 2011 research expedition were to collect data on benthic and reef fish communities; sponges and nutritional sources of the sponge community; seabirds and marine mammals; water quality, water velocity and other physical parameters. A multidisciplinary team conducted video and visual surveys on benthos, fish and sponges during 10 SCUBA dives at 20-30m depth, while sea birds and marine mammals were surveyed by means of on-board visual surveys and acoustic data loggers. Water velocity and water quality were also measured on-board using an Acoustic Doppler Current Profiler (ADCP) and Conductivity, Temperature and Depth (CTD) device.

During the expedition 8 sponge species were collected and 37 scleractinian coral species and 85 fish species were identified.Fish biomass varied per site between 1.3 kg to 4.4 kg.
Part of the measurements on water velocity, water quality and benthic cover are still in the process of being analysed. Data collected will also be used as baseline for future monitoring and analyses of biodiversity and key ecological processes within the framework of the 2011-2016 research program. 

The Indo-Pacific lionfishes (Pterois volitans [Linnaeus, 1758] and P. miles [Bennett, 1828]: Family Scorpaenidae) are the first nonnative marine fishes to establish in the Western North Atlantic/Caribbean region. The chronology of the invasion was reported last year (Schofield 2009) using records from the US Geological Survey’s Nonindigenous Aquatic Species database. This article provides an update of lionfish geographic spread (as of October 2010) and predictions of future range

Field and laboratory observations of feeding by invasive Pacific red lionfish Pterois volitans were conducted during June through August of 2008, 2009 and 2010 near Lee Stocking Island, Bahamas. Observations of this invasive marine predator revealed a previously undocumented piscivorous behavior. While slowly approaching prey fish, lionfish produce jets of water directed toward their prey. These jets may confuse or distract prey, and often result in prey fish facing the attacking lionfish, increasing the probability of head-first capture and swallowing. While a variety of fishes are re - ported to create directed water jets, to our knowledge, this is the first report of a fish that does so during the capture of fish prey. This behavior may confer a high degree of predatory efficiency, and thus contribute to the dramatic success of this Pacific invader of tropical Western Atlantic and Caribbean coral reefs

Corals in the genus Acropora generate much of the structural complexity upon which coral reefs depend, but they are susceptible to damage from toxic seaweeds. Acropora nasuta minimizes this damage by chemically cuing symbiotic goby fishes (Gobiodon histrio or Paragobiodon echinocephalus) to remove the toxic seaweed Chlorodesmis fastigiata. Within minutes of seaweed contact, or contact from only seaweed chemical extract, the coral releases an odor that recruits gobies to trim the seaweed and dramatically reduce coral damage that would otherwise occur. In turn, chemically defended gobies become more toxic after consumption of this noxious alga. Mutualistic gobies and corals appear to represent a marine parallel to terrestrial ant-plants, in that the host provides shelter and food in return for protection from natural enemies

Abstract:

In 2009, the first lionfish (Pterois volitans/miles) was found in the Parque Nacional Arrecifes de Cozumel, in Quintana Roo, in the Mexican Caribbean; however, no official record was published about this finding but just anecdotic evidence. Early in 2010, we organized workshops to lobster diver-fishermen from the northern Yucatan Peninsula on lionfish biology and potential threat of invasion, and invited them to safely collect lionfish and record basic information. In late 2010, a fisherman captured the first lionfish for the Gulf of Mexico 130 km off the northern Yucatan coast, and 50 km off eastern Alacranes Reef National Park (ARNP). Fishermen showed positive responses; thus, more workshops were organized. From 2010 to 2011, about 445 lionfish (90 - 274 mm TL) were voluntarily collected by fishermen: 1) along the coast: El Cuyo (N = 53; size range 110 - 195 mm TL), Las Coloradas (n = 1; 186 mm TL), Río Lagartos (n = 81; 139 - 327 mm TL), San Felipe (n = 2; 255-274 mm TL), Dzilam de Bravo (n = 9; 97 - 140 mm TL) Telchac Puerto (n = 1; 155 mm TL), Progreso (n = 3; 132 - 153 mm TL) and Sisal (n = 1; 145 mm TL) and 2) off the coast: Bajos del Norte (n = 21; 83 - 217 mm TL), ARNP (n = 269; 90 - 260 mm TL), and Cayo Arenas (n = 4; 134 - 180 mm TL). This work showed that 1) local community participation on conservation is viable and 2) the lionfish invaded the northern coast of the Yucatan Peninsula. This abundance represents a pale number of lionfish since collections were only on a voluntary basis. It is necessary finding ways of collaboration with monitoring initiatives in the Mexican Caribbean and establishing others (Campeche and Veracruz) to reach decisive actions for the lionfish invasion in Mexico.