Abundance Of Fish Larvae Research Articles

Distribution, abundance and ecological relevance of pelagic fishes in the Lazarev Sea, Southern Ocean

The distribution and abundance of larval and postlarval fishes was investigated in the Lazarev Sea, Southern Ocean, in March and April 2004. The upper 200 m of the water column were sampled with an 8 m 2 rectangular midwater trawl at 93 stations. The larval species community clus- tered in a diverse coastal community with high densities of Antarctic silverfish Pleuragramma antarcticum larvae and a less diverse offshore community dominated by Antarctic jonasfish Notolepis coatsi and the lanternfish Electrona antarctica. No postlarval fish were caught in coastal areas. The offshore community of postlarval fishes consisted of the deep-sea smelt Bathylagus antarcticus, and the lanternfishes Gymnoscopelus braueri, G. nicholsi and E. antarctica. The latter species clearly dominated, occurring at mean individual and wet mass densities of 0.17 individuals m -2 and 0.26 g m -2 , respectively. A generalized additive model significantly related the density of postlarval E. antarctica to the abundance of Antarctic krill Euphausia superba, ocean depth and sea surface tem- perature. The diet of E. antarctica was dominated by copepods and euphausiid larvae. Mean energy density of E. antarctica in the upper 200 m was 2.8 kJ m -2 , which is equivalent to 36% of the energy stored in Antarctic krill stocks and probably would be considerably higher if a greater depth range were considered. This suggests that E. antarctica is a major energy transmitter in the food web of the Lazarev Sea, challenging the classical krill-dominated food web paradigm of the Southern Ocean.

The abundance and distribution of teleost fish larvae in İzmir Bay.

The abundance and distribution of teleost fish larvae in İzmir Bay.

Abundance and diversity of coastal fish larvae as indicators of recent changes in ocean and climate conditions in the Oregon upwelling zone

We examined ichthyoplankton sampled from 2 stations, 9 and 18 km offshore of Newport, Oregon, USA, over a decade of cruises every 2 wk from 1996 to 2005. The 10 most dominant taxa comprised approximately 87.3% of the total catch. Concentration of fish larvae was highest in January to March, whereas diversity peaked from March through May. Both overall diversity and density of larval fishes were relatively constant throughout the period of 1996 to 2003, with a dramatic decrease in these metrics since 2004, especially for winter-spawning (January−May) species. During cool years (1999−2002), the assemblage was dominated by northern or coastal taxa such as sand lance Ammodytes hexapterus, sanddabs Citharichthys spp., and smelts Osmeridae, whereas in warm years (2003−2005), southern or offshore taxa such as English sole Parophrys vetulus, northern anchovy Engraulis mordax, and rockfishes Sebastes spp. were more abundant. These changes were related to concurrent shifts in the zooplankton biomass and composition off Oregon during cold and warm environmental regimes. We have identified a small subset of fish whose larvae can be monitored as indicators of warm and cold phases in the northeast Pacific Ocean.

Composition, abundance, distribution and seasonality of larval fishes in the shallow nearshore of the proposed Greater Addo Marine Reserve, Algoa Bay, South Africa

The larval fish assemblage was investigated in the shallow, nearshore region of a proposed marine protected area in eastern Algoa Bay, temperate South Africa, prior to proclamation. Sampling was conducted at six sites along two different depth contours at ∼5 m and ∼15 m to assess shore association. Larvae were collected by means of stepped oblique bongo net tows deployed off a ski-boat, twice per season for 2 years between 2005 and 2007. In total, 6045 larval fishes were collected representing 32 families and 78 species. The Gobiidae, Cynoglossidae, Clupeidae, Engraulidae and Sparidae were the dominant fish families. Catches varied significantly among seasons peaking in spring with a mean of ∼200 larvae/100 m 3. Mean overall larval density was higher along the deeper contour, at ∼15 m (40 larvae/100 m 3). The preflexion stage of development dominated catches at the ∼5 m (80%) and ∼15 m (73%) depth contours. Body lengths of Argyrosomus thorpei, Caffrogobius gilchristi, Diplodus capensis, Heteromycteris capensis and Solea turbynei, all estuary associated species, were larger at the shallow sites nearer to shore. Larvae of coastal species that produce benthic eggs dominated catches (75%) in the shallow sites (∼5 m) but were less abundant (32%) farther from shore at the deeper (∼15 m) sites. All developmental stages of D. capensis, Engraulis capensis, H. capensis, Sardinops sagax and two Pomadasys species were found in the study area. It appears that some species use the shallow nearshore as a nursery area.

Abundance and Diversity of Coral Reef Fish Larvae at Hurghada,Egyptian Red Sea

he larvae of coral reef fishes have been studied in Hurghada at the Egyptian Red Sea on exposed and sheltered inshore and offshore sites. Ichthyoplankton samples were taken by plankton net of 0.5 mm mesh size on a monthly basis from January to December 2005. The total abundance of fish larvae at all sites was 1993/1000m 3 . There were significant differences in larval abundance between sites and months. The sheltered inshore site (H3) showed a significantly higher abundance of all sites, whereas the exposed inshore Abu Sadaf site had the lowest abundance. The most abundant 10 taxa were Atherinomorus lacunosus (Atherinidae), Spratelloides delicatulus (Clupeidae), Gerres oyena (Gerreidae), Hypoatherina temmincki (Atherinidae), Petroscirtes mitratus (Blennidae), Vinciguerria mabahiss (Phosichthyidae), Enneapterygius sp. (Triptrygiidae), Mulloides flavolineatus (Mullidae), Benthosema pterotum (Myctophidae) and Gobiidae, forming about 82.5% of all collected larvae. The most dominant species was Atherinomorus lacunosus, contributing 1٩% of all taxa with a total abundance of ١١٣ larvae/1000m 3 . Larvae of families Siganidae and Soleidae were the least abundant both with 0.23 larvae/1000m 3

Coping with hydrogeomorphic variations in a prairie river: resiliency in young‐of‐the‐year fishes

AbstractYoung‐of‐the‐year (YOY) fish in sand‐bed rivers of grassland ecoregions frequently encounter dynamic habitat conditions produced by highly variable flow and resulting changes in geomorphic complexity of the river. How these vulnerable life history stages cope with changes in habitat condition and location is largely unknown. Therefore, we examined biodiversity and abundance of YOY fish (larvae and juveniles) at two spatiotemporal scales in response to dynamic flow conditions in the Kansas River. During the summer of 2004, we collected and identified 13 745 YOY fish from various moderate to zero‐flow habitats. Patterns of community structure through time were compared with the river's hydrogeomorphic characteristics, as determined by aerial photographs and measurements of instream flow rate and other water quality characteristics.Our initial hypothesis was that species richness and total YOY abundance would be maximized in larger and longer‐lived slackwater habitats. In contrast, our data suggest that dominant fishes in these highly dynamic ecosystems have adapted to hydrological variations with a more generalist lifestyle by either: (i) temporarily using higher flow habitats (except possibly the thalweg) to cope with intermittent loss of prime habitat; or (ii) extending spawning through favourable and demanding conditions. In contrast to current theories, our results suggest that conditions for YOY success are optimized in dynamic prairie rivers during the intermediate flows that maximize habitat heterogeneity and availability. Copyright © 2007 John Wiley & Sons, Ltd.

Ichthyoplankton in the Nacional Natural Park Isla Gorgona (Pacific Ocean of Colombia) during September 2005

The taxonomy, spatial distribution, and abundance patterns of ichthyoplankton collected in September 2005 from the coastal zone of Gorgona Island National Natural Park in the Colombian Pacific Ocean were analyzed. The ichthyoplankton in the study area was collected with oblique tows using a minibongo net (30 cm; 250 μm mesh). The tows were made from variable depths depending on the stations but never exceeding 50 m. A sampling grid with 24 stations was used. Fish larvae abundance was between 69 and 16,837 larvae·1000 m -3 . Larval stages of 35 species belonging to 14 families were identified. Gobiidae (35%) and Sciaenidae (15%) were the most abundant and frequent families. Lythrypnus sp. (8,519 larvae·1000 m -3 ) and Sciaenidae spp. (6,553 larvae·1000 m -3 ) were the most abundant and frequent species. The analysis of larval spatial distribution suggested a tendency to aggregate towards the south of the study zone, approximately 5 km offshore. Significant differences were detected in the ichthyoplankton abundances between the eastern and the western zones of the study area (Mann-Whitney, p = 0.000062). However, no significant relationship was observed between ichthyoplankton abundance and average temperature (Spearman, R = -0.346), salinity (Spearman, R = 0.227), and water transparency (Spearman, R = 0.10).

Regional and temporal variation of Oithona spp. biomass, stage structure and productivity in the Irminger Sea, North Atlantic

Oithona spp. standing stock and production is considered relatively stable in space and time as a result of continuous breeding, low metabolism, reduced predation mortality and the ability of these small cyclopoids to exploit microbial food webs more efficiently than larger copepods. However, through a review of the published literature, we show that Oithona spp. biomass can vary widely both over the year and with latitude. Thus, the present study set out to investigate the basin scale variability in biomass, stage structure and reproduction of Oithona spp. in relation to changes in hydrographic, physico-chemical and biological parameters encountered during three cruises conducted between April and November 2002 in the Irminger Sea, North Atlantic. Here we found that Oithona spp. biomass varied significantly with temperature and with dinoflagellates biomass concentration. On the other hand, Oithona similis egg production rates increased with both ciliates and dinoflagellates concentrations, rather than with temperature. The inverse relationship we found between Oithona spp. naupliar recruitment with Calanus spp. and fish larvae abundance suggests that predation pressure may contribute to control the spatial variation in the stage structure and biomass of Oithona spp. and that the nauplii of this genus may serve as a food source for other planktonic organisms prior to the spring phytoplankton bloom.

Composition, abundance, distribution and seasonality of larval fishes in the Mngazi Estuary, South Africa

We investigated the larval fish assemblage in the intermittently-open Mngazi Estuary, in the subtropical/warm-temperate biogeographic boundary region of South Africa. Larvae were collected by means of boat-based plankton tows in summer and winter for a period of three years between 2003 and 2005. Within the Mngazi Estuary, salinity ranged from 10.1–37.4, temperature ranged from 15.5°C–27.3°C, pH ranged from 6.8–8.3ppt and oxygen ranged from 2.6mg l−1–8.8mg l−1. In total, 8 343 larval fishes were collected, representing 18 families and 31 species. Clupeidae and Gobiidae were the dominant fish families whilst the dominant species was the estuary-resident Gilchristella aestuaria (Clupeidae). Estuary-resident larvae were the dominant group in the system. Larval fish density ranged from 0–38 600 individuals per 100m3 in summer and from 0 to 638 individuals per 100m 3 in winter. Species diversity also varied seasonally. Salinity zones played a significant role in terms of species distribution. The euhaline zone supported the highest species diversity while the mesohaline zone supported the highest densities of larval fishes. Salinity, temperature and turbidity were identified as important variables governing larval fish dynamics in the system.

Relationships between fish larvae and siphonophores in the water column: effect of wind-induced turbulence and thermocline depth

Abstract Sanvicente-Añorve, L., Alatorre, M. A., Flores-Coto, C., and Alba, C. 2007. Relationships between fish larvae and siphonophores in the water column: effect of wind-induced turbulence and thermocline depth. – ICES Journal of Marine Science, 64: 878–888. The relationship between the abundance of fish larvae and siphonophores in relation to wind-induced turbulence and thickness of the mixed layer in the southern Gulf of Mexico were studied during two periods of different wind conditions: April (5.25 m s−1) and October (6.5 m s−1). The Spearman correlation between fish larvae and siphonophores revealed a random relationship in the 0–10 m layer during April and in the 0–20 m layer in October. This structure presumably persists while turbulent forces remain at sufficient strength. Positive patterns were observed deeper in the water column. Whereas thermocline position did not correspond with the depth separating random and positive relationships, low turbulence values did. Observations indicate that turbulent kinetic energy values above 4 × 10−4 J kg−1 might promote a random distribution between potential prey and predator zooplankton taxa. In surface waters, contact rates between siphonophores and fish larvae showed that turbulence enhances encounters 2.5 (1.2) times in April and 3.3 (1.3) times in October for prey velocities of 0.003 (0.011) m s−1. The positive relationship between fish larvae and siphonophores could be caused by a high degree of spatial overlap, enough food for both groups, and limited predation on larvae in the presence of alternative prey. Seasonal variability in the vertical structure of distribution patterns was attributed mainly to aggregative feeding behaviour of organisms and disruption of patches as a consequence of small-scale water turbulence.

Mesoscale high-frequency variability in the Alboran Sea and its influence on fish larvae distributions

This work analyses a multidisciplinary data set including hydrological and meteorological data, satellite images, and fish larvae abundance from a high-frequency experiment conducted along a north–south transect across the Western Alboran Sea anticyclonic gyre. Four consecutive occupations of the transect, crossing the frontal area, evidenced the high-frequency variability of hydrological structures and its influence on the latitudinal and vertical distribution of fish larvae in a period of a few days. The influence of dynamical processes on fish larvae depends on the location of the spawning as well as on the larval fish position in the water column. Wind induced upwelling and/or the southward drift of the Atlantic current transport larvae of neritic species, such as Sardina pilchardus and Engraulis encrasicolus to open sea areas. At the same time, these events bring about alterations in the latitudinal and vertical distributions of mesopelagic fish larvae. The species with a relatively surface distribution, as Ceratoscopelus maderensis, were transported and accumulated to the south of the Atlantic Jet (AJ), while those with a deeper distribution in the water column, as Maurolicus muelleri or Benthosema glaciale, would be upwelled and concentrated to the north. This study shows that it is difficult to extract conclusions about the mean or preferential distributions of fish larvae when one single/synoptic survey is considered and that time evolution of hydrological structures has to be considered in order to conclude.

Winter spatial distribution of fish larvae assemblages relative to the hydrography of the waters surrounding Taiwan

The aim of this study was to investigate the species composition and distribution of fish larvae in relation to hydrographic conditions in the waters surrounding Taiwan Island (TI) in February 2003. In total, 242 kinds of fish larvae belonging to 127 genera and 75 families were recognized. Among these, 109 taxa were identified to the family or genus level, others to the species level. The 12 predominant types, which constituted 71% of the total fish larvae, were Engraulis japonica, Scomber sp., Diaphus spp., Benthosema pterotum, Carangoides ferdau, Embolichthys mitsukurii, Maurolicus sp., unidentified Myctophidae, Gonostoma gracile, Trichiurus lepturus, unidentified Gobiidae, and Myctophum asperum. The distribution of fish larvae showed a clear association with water masses around TI, with higher abundances and lower species richness northwest of TI where the China Coastal Current prevails, and lower abundances and higher species diversity east of TI where the Kuroshio Current dominates. Cluster analysis distinguished three station groups and four species groups, and the distribution patterns of fish larvae also corresponded to hydrographic conditions. The total abundances of fish larvae and eight of the 12 predominant taxa showed significant and positive correlations with zooplankton abundance, which suggests that food source might be a key factor determining the abundance and distribution of fish larvae during the winter.

Tidal and diurnal variations in larval fish abundance in an estuarine inlet in Ariake Bay, Japan: implication for selective tidal stream transport

AbstractWe have conducted a preliminary study of tidal and diurnal variations in the distribution of dominant larval and juvenile fishes in the Chikugo River inlet (Ariake Bay, Kyushu, Japan) to determine whether selective tidal stream transport (STST) occurs. Larval and juvenile fish were collected from the mesohaline zone of the Chikugo River inlet during spring 2002. Temperature, salinity, depth, and current velocity were measured. Larval and juvenile abundance were compared among four tidal conditions, flooding tide, high tide, ebbing tide, and low tide, and between day and night. A total of 12 families, 15 species, and 5,577 individuals were collected. Temperature did not vary significantly with tidal conditions whereas salinity, depth, and current velocity varied significantly. Salinity also was correlated significantly and positively with depth. The abundance of most of the fishes was correlated positively and significantly with salinity and depth. Lateolabrax japonicus, Trachidermus fasciatus, Acanthogobius hasta, and other gobiid larvae (Gobiidae spp.) were significantly more abundant during high tide; in contrast, Coilia nasus and Neosalanx reganius were most abundant during low tide. The abundance of most of the fishes was higher during high tides at night than during the day, indicating the existence of STST, which may be strategically associated with ascending progress to upstream nursery areas.

The influence of flood cycle and fish predation on invertebrate production on a restored California floodplain

Although floodplains are known to be tightly controlled by the flood cycle, we know comparatively little about how flooding influences predators and their consumption of secondary production, particularly in highly seasonal floodplains typical of Mediterranean climates. In this study, we investigate how the seasonal dynamics of a central California floodplain influence the timing and magnitude of fish predation and the abundance and composition of invertebrates. For 3 years (2000–2002), we compared changes in abundances and size distributions of invertebrates through the flood season (January–June) with seasonal changes in the abundance of larval and juvenile fishes. Using diet analysis of fishes and manipulative feeding experiments with fishes in field enclosures, we link specific changes in invertebrate populations directly to feeding preferences of seasonally abundant fish. Early in the flood season prior to March, we found little influence of fish predation, consistent with the near absence of larval and juvenile fishes during this period. Coinciding with the midseason increase in the abundance of larval and juvenile fishes in April, we found significant declines in zooplankton abundance as well as declines in the size of zooplankton consistent with fish feeding preferences. Our results were consistent with results from feeding enclosure experiments that showed that fish rapidly depressed populations of larger cladocerans with much less effect on smaller cladocerans and calanoid copepods. At the end of the flood season, zooplankton abundances rapidly increased, consistent with a switch in the feeding of juvenile fish to aquatic insects and subsequent fish mortality. We also found that zooplankton biomass on the floodplain reached a maximum 2–3 weeks after disconnection with the river. We suggest that floodplain restoration in this region should consider management strategies that would ensure repeated flooding every 2–3 weeks during periods that would best match the peaks in abundance of native fishes.

Spatial and temporal distribution of the early life stages of three commercial fish species in the northeastern shelf of the Gulf of Cádiz

Abstract Monthly cruises were carried out during an annual cycle in a coastal fringe located at the northeastern shelf of the Gulf of Cadiz, characterised by its important and diverse fishery activity, in order to study the ichthyoplankton abundance, composition and seasonality. From March 2002 to March 2003, the abundance of fish eggs and larvae was estimated monthly at 26 sampling stations in the area. The mean abundance through the analysed period was 955 eggs/100 m 3 and 326 larvae/100 m 3 of the total species of fish caught. Higher mean densities occurred during the warmest months. Three commercially important species in the area (anchovy Engraulis encrasicolus , sardine Sardina pilchardus and wegde sole Dicologlossa cuneata ) represented 57% and 50% of mean fish eggs and larval concentrations, respectively. Anchovy eggs and larvae were the most abundant in the area, each representing 33% of the total mean fish egg and larval concentrations. Temporal variations in the abundance of eggs and larvae showed different reproduction patterns for the analysed species: while anchovy reproduction mainly occurred during the spring–summer period, sardine reproduced during autumn–winter whereas wedge sole was mainly winter–spring spawner in the area. Furthermore, the spatial distribution was different for the early stages of these three species. Cluster analysis of the sampling stations (based on Bray–Curtis similarities derived from the annual mean concentrations of eggs and larvae of the three species) revealed four well-defined areas: a coastal western sector, a coastal eastern sector, an offshore sector and a single sampling station, close to the Guadalquivir River mouth, which showed a high degree of accordance with the oceanographic characterisation of the area.

Annual cycle of clupeiform larvae around Gran Canaria Island, Canary Islands

AbstractThe distribution and abundance of fish larvae was studied along the eastern and southern shelf of Gran Canaria Island (Canary Islands) from July 2000 to June 2001. Oblique bongo hauls were carried out fortnightly during the daytime, coinciding with days of full and new moon. During February, the area was sampled every 2–5 days. About 17.3% of the ichthyoplanktonic community was composed of clupeiform larvae: 92.9% of these larvae were Sardinella aurita, whereas 4.7% and 2.4% were respectively Engraulis encrasicolus and Sardina pilchardus. Sardinella aurita larvae appeared during the whole year with two periods of maximum abundance: June to September and December to February. During the full moon their abundance was on average 38.5% (±6.8%) of their numbers during the new moon, showing a clear lunar periodicity. Engraulis encrasicolus larvae appeared from November to March, also coinciding with the new moon. Sardina pilchardus larvae only appeared during two short periods, both coinciding with filaments shed from the African coastal upwelling which reached the island. This fact confirms the transport of fish larvae from the upwelling area off northwest Africa to the Canary Islands, promoting a genetic flow among both sites.

Occurrence patterns of mesopelagic fish larvae in Sagami Bay, central Japan

The species composition, seasonal abundance, and vertical distribution of mesopelagic fish larvae are described based on discrete depth sampling from the surface down to 1000 m depth during four cruises at a fixed sampling station in Sagami Bay. The abundances of total mesopelagic fish larvae in April, July, September, and December were 65.7, 13.6, 118.9, and 17.2 individuals per 10 m2 sea surface, respectively. Twenty species or types of mesopelagic fish larvae belonging to 10 families were collected. Diaphus garmani, Lipolagus ochotensis, Diogenichthys atlanticus, Sigmops gracile, and Maurolicus japonicus were the five most abundant larvae and accounted for 43.1, 14.5, 7.4, 6.3, and 5.9% of the total mesopelagic fish larvae, respectively. These five species showed clear seasonal changes in abundance, i.e. L. ochotensis, D. atlanticus, and S. gracile larvae mainly occurred during winter— spring; D. garmani and M. japonicus were collected during summer—autumn. No obvious diel vertical migration was found in these larvae. The larvae of D. garmani and M. japonicus were concentrated in the 25–50 and 50–100 m depth layers, respectively. The transforming stage of L. ochotensis, S. gracile, and D. atlanticus occurred at 400–1000 m depth, while their larvae (<8 mm standard length) occurred in the upper 100 m layer, indicating that metamorphosis of these species takes place in the 400–1000 m layer. Based on the occurrence of mesopelagic fish larvae and oceanographic processes in Sagami Bay, with the exception of D. garmani and M. japonicus, most larvae are considered to originate from the Kuroshio region where their main spawning grounds are formed.

Mesoscale physical processes and the distribution and composition of ichthyoplankton on the southern Brazilian shelf break

AbstractThe southern Brazilian shelf supports the largest fish stocks in the country, and studies on physical–biological processes in the ecology of ichthyoplankton have been recommended to provide a better understanding of the variability of the recruitment of fishing resources. This study is the first to examine the influence of mesoscale physical processes on the distribution of early life stages of fish in this shelf‐break region. Collections of fish eggs and larvae and measurements of temperature and salinity were made at 13 stations along cross‐shelf transects in December 1997. Myctophidae, Bregmacerotidae, Clupeidae, Synodontidae and Engraulidae were the most abundant larvae in the northern region, while Engraulidae and Bregmacerotidae prevailed further south. In situ hydrographic data, NOAA/AVHRR images and merged TOPEX/POSEIDON + ERS‐1/2 satellite altimetry taken during the cruise revealed an anticyclonic eddy dominating the shelf around 31°S. Larval fish abundance was lower at the centre of this feature, suggesting that the eddy advected poorer offshore waters of tropical origin towards the inner shelf‐concentrating the larvae around the eddy.

Summer ichthyoplankton, food supply of fish larvae and impact of invasive ctenophores on the nutrition of fish larvae in the Black Sea during 2000 and 2001

Qualitative composition and abundance of both ichthyoplankton and small forms of zooplankton were evaluated by field studies in the northern (the Crimea near Sevastopol) and southern (Sinop region and TEEZ) Black Sea during the summers 2000 and 2001. A tendency of increasing the species richness, abundance of fish eggs and larvae as well as zooplankton (which is the food for fish larvae) was observed over a period of Mnemiopsis leidyi and Beroe ovata co-existence. The eggs and larvae of the Mediterranean migrants—bonito and bluefish appeared again in the coastal waters near Sevastopol, which testified to favourable conditions for the spawning and nutrition of these fish species and their larvae. Aborigen copepod Oithona nana was found in the Crimean coastal waters although earlier in the 1990s it had completely vanished. Although rare in the 1990s copepods Centropages ponticus and Paracalanus parvus appeared in inshore waters as well as Pontellids species. Observed increases in species number and abundance of both ichthyoplankton and small zooplankton (≤500 μm), which promoted survival and development of fish larvae, were attributed to reduced predatory impact of Mnemiopsis on prey zooplankton after the arrival of Beroe in the late 1990s. However, the influence of Mnemiopsis continued to be significant during the short period of its peak occurrence in late summer. When this period coincided with the appearance of fish larvae, a negative impact on their survival could be predicted due to a low concentration of food items for larvae feeding.

A Coupled Asymmetrical Multiple Opening Closing Net with Environmental Sampling System

Recruitment levels of fishes are potentially related to the abundance of larval fishes and their food source. A system that could allow for the concurrent investigation of fine-scale distribution of fish larvae and their potential prey could add significantly to the understanding of the early life history of marine fishes. A coupled Multiple Opening Closing Net and Environmental Sensing System (MOCNESS) that combines two sub-systems (1 m2 and 4 m2 net sets) working in synchronization was designed to answer these questions. The mesh size was different on each set of nets allowing the collection of a broad size range of organisms while optimizing the catch of larger fish larvae and eliminating unnecessary large samples of zooplankton. Moreover, the system eliminated the need to deploy separate MOCNESS using different mesh sizes, thus reducing ship time costs, and avoiding any aliasing associated with trying to sample the same water mass with separate nets fished sequentially. The system has been used at sea under varying weather conditions onboard the R/V F. G. Walton Smith and sampled adequately.