Identification And Distribution Of Urophycis And Phycis (Pisces, Gadidae) Larvae And Pelagic Juveniles In The United-States Middle Atlantic Bight

Analysis of surface and subsurface plankton collections in the Middle Atlantic Bight (MAB) yielded larvae and juveniles of Phycis chesteri and five species of Urophycis. Identification was based on numbers of epibranchial gill rakers, abdominal vertebrae, and. fin rays (dorsal, caudal, pelvic), patterns of pterygiophore interdigitation, and morphometric characters including body depth at the vent and a ratio between height of the pelvic-fin base and length of the mandible. Urophycis tenuis accounted for 99% of the Urophycis larvae and pelagic juveniles collected during spring off Virginia and New Jersey and was most abundant offshore. Urophycis tenuis larvae were smallest at off-shore stations and increased in size as collections proceeded shoreward. Urophycis chuss was found in summer and fall collections off the coasts of New Jersey and Virginia, with abundances highest at midshelf stations. Urophycis chuss was the only species of hake found during August and early September, and it dominated summer ichthyoplankton collections. Urophycis regia was found primarily in midshelf areas off Virginia during fall, but was also collected offshore from both Virginia and New Jersey during winter. Phycis chesteri, also found in fall and winter collections, was restricted to offshore stations. Southern species, found exclusively in offshore winter collections, included U. floridana and U. cirrata

Distribution, Abundance, and Feeding Habits of Juvenile Kingfish (Menticirrhus) Species Found in the North-Central Gulf of Mexico

Southern Kingfish (Menticirrhus americanus), Gulf Kingfish (Menticirrhus littoralis), and Northern Kingfish (Menticirrhus saxatilis) were collected by beam plankton trawl and seine along shoreline habitats in 2005 and 2006. Specific habitats included barrier island (surf zones and grass beds) and mainland (marsh edge and sandy shorelines) areas. Five hundred sixty-seven kingfish were collected during this study, with over 85% of the specimens collected in 2006. Densities of both M. americanus and M. littoralis peaked during summer, whereas densities of M. saxatilis peaked in spring. All three kingfish species co-occurred within surf zone and sandy shoreline habitats, but M. americanus was the dominant kingfish along protected sandy shorelines, and M. littoralis was the dominant kingfish along open surf zones. Several M. littoralis, which are known to be surf zone species, were also collected from mainland sandy shoreline. Only M. americanus was collected from marsh edges, and all three species were absent from grass beds. Stomachs of all three kingfish species at sizes \u3c 15 mm standard length (SL) most often contained calanoid copepods. Larger M. americanus (16–60 mm SL) fed most frequently on mysids, larger M. littoralis (31–60 mm SL) fed most frequently on bivalves, and larger M. saxatilis (31–60 mm SL) fed most frequently on both mysids and amphipods. The diversity of prey items increased with size for all three Menticirrhus species. This research provides a useful descriptive report on the distribution, abundance, and feeding habits of juvenile Menticirrhus species found in the north-central Gulf of Mexico

Diel Vertical Distribution of Atlantic Croaker, \u3ci\u3eMicropogonias undulatus\u3c/i\u3e, Larvae in the Northcentral Gulf of Mexico With Comparisons to Red Drum, \u3ci\u3eSciaenops ocellatus\u3c/i\u3e

Atlantic croaker Micropogonias undulates (Linnaeus, 1766) larvae \u3c 6 mm showed a distinct pattern of vertical stratification in inner-shelf waters (\u3c 25 m depth) of the northcentral Gulf of Mexico. Discrete-depth plankton collections were taken at night, early morning after daylight, and at mid-day or early afternoon at 1, 5, and 11–16 m. No consistent pattern among cruises was evident in the vertical stratification of Atlantic croaker larvae found in mid-day and afternoon collections, but at night the highest abundances were observed at the deepest depths sampled. Atlantic croaker larvae were least abundant in surface waters (1 m) at night. Of the 66,913 Atlantic croaker larvae collected, only 346 specimens (\u3c 1%) were found in 1 m collections at night, and 266 of these larvae were from a single collection of large specimens (mean = 6.7 mm). By morning the vertical distribution of larvae suggested that Atlantic croaker had moved up in the water column, and highest abundances were usually found at 5 m. There was no indication that patterns of larval distribution reflected hydrographic stratification within the water column, prey availability, size of larvae, or moonlight intensity

Small-scale spatial and temporal variability in growth and mortality of fish larvae in the subtropical northcentral Gulf of Mexico: implications for assessing recruitment success

Extensive plankton collections were taken during seven September cruises (1990–93) along the inner continental shelf of the northcentral Gulf of Mexico (GOM). Despite the high productivity and availability of food during these cruises, significant small-scale spatial variability was found in larval growth rates for both Atlantic bumper (Chloroscombrus chrysurus, Carangidae) and vermilion snapper (Rhomboplites aurorubens, Lutjanidae). The observed variability in larval growth rates was not correlated with changes in water temperature or associated with conspicuous hydrographic features and suggested the existence of less-recognizable regions where conditions for growth vary. Cruise estimates of mortality coefficients (Z) for larval Atlantic bumper (n=32,241 larvae from six cruises) and vermilion snapper (n= 2581 larvae from four cruises) ranged from 0.20 to 0.37 and 0.19 to 0.29, respectively. Even in a subtropical climate like the GOM, where larval-stage durations may be as short as two weeks, observed variability in growth rates, particularly when combined with small changes in mortality rates, can cause order-of-magnitude differences in cumulative larval survival. To what extent the observed differences in growth rates at small spatial scales are fine-scale “noise” that ultimately is smoothed by larger-scale processes is not known. Future research is needed to further characterize the small-scale variability in growth rates of larvae, particularly with regard to microzooplankton patchiness and the temporal and spatial pattern of potential predators. Small-scale spatial variability in larval growth rates may in fact be the norm, and understanding the implications of this subtle mosaic may help us to better evaluate our ability to partition the causes of recruitment variability

Assessment of larval striped bass, Morone saxatilis (Walbaum), stocks in Maryland and Virginia waters. Part II. Assessment of spawning activity in major Virginia rivers. Segment 3. Pt.A. Distribution and abundance of striped bass eggs and larvae in the Rappahannock River during spring, 1982 : final report

Segment 1. Distribution and abundance of striped bass eggs and larvae in the upper York River system, Virginia, during spring 1980 Segment 2. Distribution and abundance of striped bass eggs and larvae in the James and Chickahominy Rivers, Virginia, during spring 1981 : draft final report Segment 3. Pt.A. Distribution and abundance of striped bass eggs and larvae in the Rappahannock River during spring, 1982 : final report Segment 3. Pt.B. Dorsal and anal pterygiophore interdigitation patterns in four species of Morone (Teleostei, Percichthyidae) : an aid to larval identification https://doi.org/10.21220/V50X7

Spatio-Temporal Distribution of Larval Gobiosoma Bosc in Waters Adjacent to Natural and Altered Marsh-Edge Habitats of Mississippi Coastal Waters

Larval naked gobies, Gobiosoma bose, were collected monthly from October 1995 to September 1997 by beam plankton trawl from waters adjacent to natural Juncus/Spartina marsh-edge, natural sandy beach and altered Juncus/Spartina marsh-edge habitats in Mississippi coastal waters. Altered marsh habitats consisted of two bulkheaded stations and one stretch of riprap. Abundances were significantly higher in waters adjacent to natural marsh-edge habitats than in those adjacent to altered habitats in year one (P = 0.011), suggesting that the physical nature of alteration may have caused reduced habitat suitability. Abundances also varied seasonally, with summer conditions of high water temperature, increasing tide height, intermediate depth, low dissolved oxygen, and clear skies being significantly related to high abundance of postflexion G, bose in each year (r(2) = 0.481 and 0.276, respectively). Year two abundances were lower than those of year one and not significantly different among habitats. There was also a noticeable shift in the reproductive strategy of G. bose from a bimodal pattern in year one to a single reproductive peak in year two. This study illustrates the importance of natural Juncus/Spartina marsh-edge habitat to G. bose reproduction/recruitment and by extension to the community structure of the Back Bay/Davis Bayou estuarine ecosystem

Early Growth of Three Kingfish (Menticirrhus) Species Found in Coastal Waters of the Northern Gulf of Mexico

Southern kingfish (Menticirrhus americanus), gulf kingfish (M. littoralis), and northern kingfish (M. saxatilis) are members of the drum family (Sciaenidae) that are widespread in coastal habitats of the western Atlantic, including in the Gulf of Mexico (GOM). Despite their economic and ecological importance, little is known about growth of young kingfish. Young kingfish were collected from four different Mississippi shoreline habitats in 2005 and 2006; two associated with barrier islands and two along the mainland. Barrier island habitats included surf zones on the south shore and grass beds on the north shore. Mainland habitats were located along marsh-edges and sandy shorelines. Kingfish growth comparisons were made using analysis of covariance (ANCOVA) on 194 aged fish (127 M. americanus, 54 M. littoralis, and 13 M. saxatilis). Growth rates for all three species were generally similar ranging from about 0.7mm/day at 4-6 mm standard length (SL) to 1.9mm/day at 55-60mm SL. In 2005, M. americanus from marsh-edges grew significantly faster than those from sandy shorelines. Size-at-age of M. americanus and M. littoralis was significantly smaller in the spring than in the summer and fall, while both growth rate and size—at—age were similar in the summer and fall

Regional Patterns in the Otolith Chemistry of Juvenile Spotted Seatrout (\u3ci\u3eCynoscion nebulosus\u3c/i\u3e) Differ Under Contrasting Hydrological Regimes

The value of using otolith chemistry to characterize recruitment in terms of natal source regions depends on how consistently spatio-temporal variation can be resolved. The objective of this study was to compare regional classification patterns in the otolith chemistry of juvenile Spotted Seatrout (Cynoscion nebulosus) between two years experiencing disparate hydrological regimes, and separated by a five year interlude. Spatial patterns in the whole-otolith chemistry of juveniles of this estuarine-dependent species were compared between years using five otolith elements and two stable isotopes. Consistent size-related trends in uptake and deposition were evidenced by parallel ontogenetic relationships for six otolith variables. Nine natal regions were discerned equally well in both years; and region accounted for similar overall amounts of variation in the seven otolith variables in both years. However, the otolith variables did not distinguish the nine regions in the same manner in both years, and natal regions varied in how similar they were in otolith chemistry between years. Consequently, between-year cross-classification accuracy varied widely among regions, and geographic distance per se was unimportant for explaining regional patterns in otolith chemistry. Salinity correlated significantly with regional patterns in otolith chemistry in 2001, but not at all in 2006 when conditions were much drier. Regional patterns in individual otolith variables reflected either a general trend based on hydrology, a regional-local effect whereby geographically closer regions exhibited similar otolith chemistry, or a location-specific effect for which there was either no correlation in otolith concentration among regions between years, or a significant but individualistic relationship. In addition to elucidating limitations of using otolith chemistry to identify natal source regions or for tracking fish movements, knowing more about how and why otolith chemistry varies could be used to address specific questions about early recruitment dynamics, or to aid in the development of more reliable instruments for discerning natal source contributions

Distribution, Abundance, and Feeding Habits of Juvenile Kingfish (Menticirrhus) Species Found in the North-Central Gulf of Mexico

Southern Kingfish (Menticirrhus americanus), Gulf Kingfish (Menticirrhus littoralis), and Northern Kingfish (Menticirrhus saxatilis) were collected by beam plankton trawl and seine along shoreline habitats in 2005 and 2006. Specific habitats included barrier island (surf zones and grass beds) and mainland (marsh edge and sandy shorelines) areas. Five hundred sixty-seven kingfish were collected during this study, with over 85% of the specimens collected in 2006. Densities of both M. americanus and M. littoralis peaked during summer, whereas densities of M. saxatilis peaked in spring. All three kingfish species co-occurred within surf zone and sandy shoreline habitats, but M. americanus was the dominant kingfish along protected sandy shorelines, and M. littoralis was the dominant kingfish along open surf zones. Several M. littoralis, which are known to be surf zone species, were also collected from mainland sandy shoreline. Only M. americanus was collected from marsh edges, and all three species were absent from grass beds. Stomachs of all three kingfish species at sizes \u3c 15 mm standard length (SL) most often contained calanoid copepods. Larger M. americanus (16–60 mm SL) fed most frequently on mysids, larger M. littoralis (31–60 mm SL) fed most frequently on bivalves, and larger M. saxatilis (31–60 mm SL) fed most frequently on both mysids and amphipods. The diversity of prey items increased with size for all three Menticirrhus species. This research provides a useful descriptive report on the distribution, abundance, and feeding habits of juvenile Menticirrhus species found in the north-central Gulf of Mexico

Otolith Chemistry of Juvenile Spotted Seatrout \u3ci\u3eCynoscion nebulosus\u3c/i\u3e Reflects Local Natal Regions of Coastal Mississippi, USA

Early juvenile spotted seatrout Cynoscion nebulosus (n = 199) were collected during late summer and autumn 2001 from shoreline habitats within 9 coastal regions bordering Mississippi Sound in the north-central Gulf of Mexico to ascertain how well fish could be spatially classified based on otolith chemistry. Left otoliths were assayed for trace element:Ca ratios of Ba, Li, Mg, Mn and Sr, and right otoliths for delta(13)C and delta(18)O. Significant overall differences in otolith chemistry existed among the 9 regions; 61 % of the joint variance in the 7 otolith chemistry variables was explained by the regional factor in a multivariate analysis of variance (MANOVA). All 7 otolith chemistry variables differed significantly among the 9 regions. The isotopes delta(13)C and delta(18)O showed the highest regional affinities, and Li showed the strongest regional association of all the trace elements. Canonical discriminant function analysis (CDFA) maximally separated regional groups of early juvenile fish. The first 3 of 7 discriminant functions accounted for 97.5 % of the cumulative variance in the 7 otolith chemistry variables. CDF 1 was influenced primarily by delta(18)O and Li, CDF 2 by Mn and delta(13)C, and CDF 3 by Mg and Ba. In the all-inclusive CDFA, 93.4 % of cases Were classified correctly, and classification success among regions ranged from 83.3 to 100%. The influence of freshwater discharge from 7 rivers along the Mississippi coastline likely made it possible to detect the relatively fine-scale spatial differences seen in this study, as defined by a mean interregional distance of only 25 km