Atlantic Menhaden Research Articles

Comparison of Soy and Fish Oils in Practical Diets for Fingerling Walleyes

AbstractA 63‐d feeding trial was conducted to compare growth and other performance variables of feed‐trained juvenile walleyes Sander vitreus fed an open‐formula diet containing 10% soy oil (SO) as a replacement for 11.75% Atlantic menhaden Brevoortia tyrannus oil that is used in the commercially manufactured walleye grower diet (WG). The SO diet was formulated to be identical to the WG formulation except for the oil. The feeds contained 46% crude protein and similar gross energy (SO: 1,121 J/g; WG: 1,192 J/g). Fish were stocked (209 fish; 5.1 g/L) into triplicate 1,000‐L tanks. Fish were fed 7% body weight/d during a 16‐h light period with in‐tank lighting. Juvenile walleyes were 157 d old, 124 ± 1.0 mm in total length (mean ± SE), and 24.4 ± 0.71 g at the start of the trial. Differences between treatment in relative growth, specific growth rate, survival, final mean length, and mean weight between treatments were not statistically significant. Although derived from a short‐term trial, the findings suggest that SO at 10% is a suitable replacement for nearly 12% marine fish oil in a feed for juvenile walleyes. In 2007, the cost of Atlantic menhaden oil in the WG formulation was 1.6‐fold greater (US.39/0.454 kg) than that of the SO (.29/0.454 kg) used in the diets.

Brevetoxin in two planktivorous fishes after exposure to Karenia brevis: implications for food-web transfer to bottlenose dolphins

Brevetoxin uptake was analyzed in 2 common planktivorous fish that are likely food- web vectors for dolphin mortality events associated with brevetoxin-producing red tides. Fish were exposed to brevetoxin-producing Karenia brevis for 10 h under conditions previously reported to produce optimal uptake of toxin in blood after oral exposure. Striped mullet Mugil cephalus were exposed to a low dose of brevetoxin, and uptake and depuration by specific organs were evaluated over a 2 mo period. Atlantic menhaden Brevoortia tyrannus specimens were used to characterize a higher brevetoxin dose uptake into whole body components and evaluate depuration over 1 mo. We found a high uptake of toxin by menhaden, with a body to water ratio of 57 after a 10 h exposure and a slow elimination with a half life (t 1/2) of 24 d. Elimination occurred rapidly from the intestine (t 1/2 < 1 wk) and muscle (t 1/2 ≈ 1 wk) compartments and redistributed to liver which continued to accumulate body stores of toxin for 4 wk. The accumulation and elimination characteristics of the vectoring capacity of these 2 fish species are interpreted in relation to data from the Florida Panhandle dolphin mortality event of 2004. We show that due to slow elimination rate of brevetoxin in planktivorous fish, brevetoxin-related dolphin mortality events may occur without evidence of a concurrent harmful algal bloom event.

Fluctuating asymmetry in the otoliths of larval Atlantic menhaden Brevoortia tyrannus (Latrobe) – a condition indicator?

Fluctuating asymmetry (FA) was described for otolith length, width and area for two groups of larval and juvenile Atlantic menhaden Brevoortia tyrannus. The larvae and juveniles (age range: 20–120 days; standard length, LS, range: 14–35 mm) were separated into the two distinct groups a priori on the basis of their growth indices estimated from residuals of a LS‐at‐age model; slow growers had residuals &lt;8% of the average size at age and fast growers had residuals &gt;8%. Some indication supporting the fluctuating asymmetry methodology was found when unsigned normalized FA2 index was used for otolith area. That conclusion was not, however, supported by the other method used in this work, i.e. between‐group ANCOVA analysis of individual unsigned and not normalized FA1 indices plotted against trait size. These inconsistent results are most probably a consequence of error introduced during FA index normalization (accounting for trait size effect on absolute FA). Although it is concluded here that FA analysis of sagittal otoliths was not effective in describing differences in the natural variability of growth and condition of larval Atlantic menhaden, the possible species‐ and otolith type‐related differences should be considered in the future research on FA.

Effects of Age‐1 Striped Bass Predation on Juvenile Fish in Western Albemarle Sound

AbstractHistorically, the fisheries for adult river herring (i.e., alewife Alosa pseudoharengus and blueback herring A. aestivalis) and American shad A. sapidissima were economically important in Albemarle Sound, North Carolina. Stocks of these species are in decline, while stocks of striped bass Morone saxatilis have increased roughly 10‐fold in the Albemarle Sound‐Roanoke River since the early 1990s. The goal of this study was to quantify the predatory impact of age‐1 striped bass on age‐0 prey fishes by estimating striped bass consumption rates and comparing loss rates from predation with total prey loss rates using catch curves. Age‐1 striped bass and their potential prey were collected with beach and purse seines from western Albemarle Sound from spring to fall, 2002 and 2003. Commercially and ecologically important prey in one or both years included river herring, American shad, Atlantic menhaden Brevoortia tyrannus, and yellow perch Perca flavescens. Predation by age‐1 striped bass had a marked effect on juvenile American shad densities in 2002 but little effect in 2003. Conversely, predation by age‐1 striped bass explained none of the loss in juvenile yellow perch in 2002 but accounted for nearly all of the loss early in 2003. In most cases, predation by age‐1 striped bass did not greatly influence juvenile alewife numbers. Juvenile blueback herring were preyed on during late summer and fall, but the predatory impact could not be confirmed because of apparent downstream emigration into the study area. Thus, for some species, these predator‐prey linkages are important in determining year‐class strength and should be incorporated into multispecies population models.

Multitiered Health Assessment of Atlantic Menhaden in the Pamlico River, North Carolina

During the fall of 2001 and 2002, Atlantic menhaden Brevoortia tyrannus were collected from several creeks in the Pamlico River, North Carolina, to investigate recent fish kills and ulcerative skin lesions. High skin lesion prevalence (>50%) was associated with the Atlantic menhaden kills in fall 2001, whereas there were no fish kills in fall 2002 and skin lesion prevalence was lower (< or =50%). Indicators of tissue damage (histopathological analyses of gills, heart, liver, intestine, and anterior kidney), body condition (liver somatic index), and immune status (transforming growth factor-beta [TGF-beta] messenger RNA [mRNA] production, hematology, plasma chemistry, and splenosomatic index) were compared between Atlantic menhaden with and without ulcerative skin lesions in fall. Atlantic menhaden with ulcerative skin lesions had significantly higher liver somatic indices, neutrophil and monocyte percentages, and splenic mononuclear cell TGF-beta mRNA levels than did fish without lesions. Hematocrit values, plasma protein, and Ca concentrations were significantly lower in fish with ulcerative skin lesions than in those without. The indicators used in this study at multiple levels of biological organization have provided valuable baseline data for understanding the health status of lesioned and nonlesioned Atlantic menhaden in the Pamlico River.

Finfish-Waterbird Trophic Interactions in Tidal Freshwater Tributaries of the Chesapeake Bay

With the DDT ban enacted in the early 1970s, piscivorous bird populations have grown exponentially throughout the tidal reach of the Chesapeake Bay. However, avian population growth is not uniform throughout the Chesapeake Bay watershed; several species including Bald Eagles (Haliaeetus leucocephalus) and Ospreys (Pandion haliaetus) experienced significantly greater population growth rates in riverine tidal freshwater and oligohaline regions than in higher salinity portions of the bay. Shifting fish prey resources may provide an explanation for the observed influence of salinity on distribution of piscivorous bird populations. Changes in the fish resources available to avian predators over the past 40 years include changing temporal and spatial distribution of fish prey, as well as shifts in taxonomic and trophic structure of resident and migratory fish assemblages. Historical ecological changes, including long- and short-term changes in the abundance of anadromous clupeid fishes, Atlantic Menhaden (Brevoortia tyrannus), and the relatively recent introduction and establishment of non-indigenous fishes, within tidal freshwater rivers may be influencing piscivorous bird distributions and abundance, particularly for Bald Eagles and Ospreys, in the Chesapeake Bay. Predator-prey interactions among piscivorous birds and fish prey have received little attention from wildlife managers. Collaborative efforts between fishery scientists and avian ecologists will ultimately lead to better ecosystem management of the Bay’s living resources.

Olencira praegustator (Crustacea, Isopoda, Cymothoidae) parasitic on Brevoortia species (Pisces, Clupeidae) from the southeastern coasts of North America: review and re-description

The cymothoid isopod Olencira praegustator (Latrobe, 1802), the sole species of the genus Olencira Leach, 1818, has been the subject of several previous studies, but has remained incompletely described. This species is re-described and figured from the Atlantic menhaden Brevoortia tyrannus (Latrobe, 1802), the type host from the estuarine systems of the South Carolina coast, USA. The general morphology, mouthparts and appendages of the female, male and other stages of its lifecycle are described. The geographical distribution and hosts recorded for O. praegustator are reviewed. Biological data are summarized and discussed. Areas that need additional studies include the infection process and the effect of the parasite on its host.

Genetic evidence for asymmetric hybridization between menhadens (Brevoortiaspp.) from peninsular Florida

Hybridization between the North American menhadensBrevoortia smithi,Brevoortia tyrannusandBrevoortia patronushas been reported by numerous authors, based primarily on the morphological intermediacy of hybrids relative to each parental type. In this study, genetic characterization of individuals in areas previously designated as hybrid zones validates the presence of F1hybrids. Evidence from microsatellite genotypes indicates thatB. patronusandB. smithiare parental species of hybrids on both sides of the Florida peninsula, and mitochondrial DNA (mtDNA) haplotypes suggest a maternal contribution byB. smithiin each case. Hybrids betweenB. tyrannusandB. smithiwere not identified in this study. The presence ofB. patronuson the Atlantic coast of Florida, coupled with admixture between this species andB. tyrannus, has likely influenced the mixed lineage assortment of mtDNA haplotypes demonstrated in this study and in previous studies.

Assessing Coastwide Effects of Power Plant Entrainment and Impingement on Fish Populations: Atlantic Menhaden Example

AbstractA method was developed for assessing coastwide effects of power plant impingement and entrainment on managed fish stocks. The method imbeds an assessment of anthropogenic effects that occur during the first year of life of fish (the period when most entrainment and impingement occur) into a standard age‐structured stock assessment that addresses age‐1 and older fish. The method thereby provides a straightforward means for comparing the effects of entrainment and impingement mortality to other forms of anthropogenic mortality affecting coastwide fish stocks. The method uses standard equations from fishery science that represent the relationships among independent competing forces of mortality, stock abundance, and landings. Power plant mortality is treated like fishing mortality, and power plant losses are treated like fishery landings. The total age‐0 natural mortality rate is allocated to the individual age‐0 life stages based on a power function relating daily natural mortality rates to age‐specific dry weights of fish. An illustrative example of the use of the method is presented for the Atlantic coast stock of Atlantic menhaden Brevoortia tyrannus, which was chosen because it is a coastwide stock, has a coastwide fishery, and is described by high‐quality fisheries‐dependent data. However, because available entrainment and impingement data were not adequate to support defensible coastwide estimates of the annual numbers killed by entrainment and impingement, actual estimates of the effects of entrainment and impingement on the coastwide Atlantic menhaden stock could not be computed. The method could be used to address the effects of any form of anthropogenic mortality affecting age‐0 fish, including loss of habitat, effects of toxic substances, fishing mortality, and fishery bycatch, provided that valid coastwide estimates of the annual numbers of fish killed by the source of mortality are available.

Historical Diet Analysis of Loggerhead Sea Turtles (Caretta Caretta) in Virginia

Digestive tract contents were examined from 297 Loggerhead Sea Turtles (Caretta caretta) in Virginia during 1983–2002. Analyses revealed a shift from predominantly Atlantic Horseshoe Crab (Limulus polyphemus) during the early to mid-1980s to predominantly Common Blue Crab (Callinectes sapidus) during the late 1980s and early 1990s. Diet in the mid-1990s and in 2000–2002 was dominated by finfish, particularly Atlantic Menhaden (Brevoortia tyrannus) and Atlantic Croaker (Micropogonias undulatus). These diet shifts suggest that horseshoe crab and blue crab population declines have caused loggerheads to forage in nets or on discarded fishery bycatch.

Feeding Channel Catfish, Ictalurus punctatus, Diets Amended with Refined Marine Fish Oil Elevates Omega‐3 Highly Unsaturated Fatty Acids in Fillets

Abstract Channel catfish, Ictalurus punctatus, 88.4 ± 2.6 g/fish, were fed a basal diet amended with 4% of three processed menhaden, Brevoortia tyrannus, oils. These were compared with basal diets amended with 4% corn oil or 4% canola oil. Three replicate aquaria of nine fish each were fed assigned diets twice daily. At 6 wk, fish were group weighed, fillets were collected for sensory evaluation, fatty acid analysis by gas chromatography (GC). In a second study, catfish, 118.8 ± 3.2 g/fish, were stocked into fifteen 0.04‐ha earthen ponds and fed once daily for 16 wk one of four diets containing 2 or 4% of either catfish offal oil or refined (RF) menhaden oil. At harvest, fillets were saved for sensory evaluation and fatty acid analysis. Results showed no significant (P &gt; 0.05) differences among treatments for aquarium study and pond study variables such as weight gain, fillet proximate analysis, or pond production. GC analysis showed that levels of omega‐3 (n‐3) highly unsaturated fatty acids (HUFA) in fillet lipid were significantly (P &lt; 0.05) elevated for fish fed menhaden oil diets. Sensory evaluation revealed that fillets from fish fed RF menhaden oil had satisfactory flavor and could be a source of n‐3 HUFA for humans.

Assessing Potential Effects of Entrainment and Impingement on Fish Stocks of the New York–New Jersey Harbor Estuary and Long Island Sound

AbstractWe assessed the potential effects of entrainment and impingement at the Charles Poletti Power Project (hereafter, Poletti) on fish stocks of the New York–New Jersey (NY–NJ) Harbor Estuary and Long Island Sound by (1) estimating, for five fish stocks, the conditional mortality rate (CMR) for entrainment of eggs, larvae, and young‐of‐the‐year (age‐0) fish and the CMR for impingement of age‐0 fish, and (2) for two of those stocks, using the CMR estimates to calculate the proportional reduction in biomass of spawners from an unfished stock under equilibrium conditions. Estimates of entrainment CMR for eggs and larvae were low and ranged from 0.02% for tautogs Tautoga onitis to 0.11% for Atlantic menhaden Brevoortia tyrannus, based on the spatial and temporal distribution of those life stages in the NY–NJ Harbor Estuary and Long Island Sound study area and the probabilities of entrainment generated by a particle tracking model, coupled with a three‐dimensional estuarine circulation model that simulated the transport of ichthyoplankton. Estimates of entrainment CMR for age‐0 fish were low and ranged from 0.00% for tautogs and winter flounder Pseudopleuronectes americanus (none were collected in entrainment samples) to 0.11% for cunners Tautogolabrus adspersus, based on age‐0 numbers entrained and standing crop estimates. Impingement CMRs ranged from 0.00% for windowpanes Scophthalmus aquosus (none were impinged) to 0.80% for tautogs. The proportional reduction in the biomass of spawners from an unfished stock would increase only 0.09% for winter flounder and 0.01% for Atlantic menhaden as a result of entrainment and impingement at Poletti. These effects are extremely small relative to the effects of fishing mortality.

Mycobacteria as Environmental Portent in Chesapeake Bay Fish Species

Infection with environmental mycobacteria is increasing among many Chesapeake Bay fish species. Prevalence in juvenile Atlantic menhaden differed between tributaries and ranged from 2% to 57%. Mycobacterial infection may be a syndromic sentinel of altered environmental conditions that threaten aquatic animal health.

Spatial and temporal differences of Atlantic menhaden (Brevoortia tyrannus) recruitment across major drainages (1966–2004) of the Chesapeake Bay watershed

Atlantic menhaden (Brevoortia tyrannus) is well known for its commercial and ecological importance and has been historically declining in the Chesapeake Bay (Maryland), one of its principal nursery habitats along the eastern coast. Using data from the Striped Bass Seine Survey of the Maryland Department of Natural Resources (2003), we evaluated how the distribution of Atlantic menhaden has changed from 1966 to 2004 for 12 river drainages. We observed significant or marginally significant declines in 42% of the drainages, with drainages of the northern Bay showing the majority of those declines. Continued recruitment to several drainages of the Bay may partly explain why the adult spawning population is not declining. We determined if temporal changes in abundance were related to changes in salinity or water quality for five major drainages of the watershed. For one of these drainages, the Patuxent River, differences in productivity across sites largely explained differences in abundance. For the four remaining drainages, differences in recruitment could not be explained by productivity or salinity gradients. While reducing nitrogen loading and enhancing water clarity may improve Atlantic menhaden production, we suggest that the role of offshore processes on large-scale declines has been largely neglected and studies on larval ingression are necessary for further elucidation of spatial and temporal patterns of juvenile distribution in the Chesapeake Bay.

Metabolism of dimethylsulfoniopropionate (DMSP) by juvenile Atlantic menhaden Brevoortia tyrannus

Dimethylsulfoniopropionate (DMSP) synthesized by marine phytoplankton is the princi- pal source of dimethylsulfide (DMS), an important climate-affecting gas. Prior research has demon- strated that grazing by invertebrate phytoplanktivores often affects the dynamics of DMS production from algal DMSP, but the effects of grazing by phytoplanktivorous fish have not previously been investigated. We studied the fate of algal DMSP following grazing by juvenile Atlantic menhaden Brevoortia tyrannus (13 cm fork length), which are generally viewed as the most specialized for phy- toplanktivory of all postlarval fish. The menhaden were fed the dinoflagellate Prorocentrum micans, containing 1 to 2 pmol DMSP cell -1 . During the first 24 h following ingestion of algal DMSP, almost none of the DMSP (ca. 1%) appeared as DMS. About 21% of ingested DMSP appeared in the water column as dissolved DMSP, peaking in concentration 9 to 11 h after feeding; in natural settings, this fraction would be poised for microbial metabolism, including potential conversion to DMS in surface waters from which outgassing to the atmosphere could occur. About 10% of ingested DMSP appeared in fecal pellets that tended to sink rapidly toward the bottom of the tanks. About 33% of ingested DMSP was deposited in the tissues of the menhaden, in particular in the red and white swimming muscles, in which we observed concentrations exceeding 0.7 µmol g -1 . This final fraction could ultimately be metabolized to DMS, or it could be passed up food chains and possibly act as a taste factor in commercially important piscivores such as striped bass and bluefish. In total, our research demonstrated that at least two-thirds of the ingested DMSP ends up in tissues or feces or in solution in the ambient water in the first 24 h after feeding, and virtually none is converted to ambient DMS during that time period.

Skippers, spotters and seiners: Analysis of the “skipper effect” in US menhaden ( Brevoortia spp.) purse-seine fisheries

Differences in weekly catch and fuel efficiency are not fully accounted for by variations in environment, effort, or vessel characteristics in the US gulf and Atlantic menhaden ( Brevoortia spp.) fisheries. In four ports analyzed, some skippers consistently had higher weekly catches, and in two of the four ports some skippers had greater catch per unit of fuel burned. Results are impressive considering these are fisheries where one might expect the skipper effect to be weak: vessels are all very similar, the fishery is vertically integrated, and sophisticated fish finding equipment is used, including spotter planes. The results suggest that skipper skill is of primary importance in catching fish; this may be generalizable to most purse-seine fisheries. These findings have importance for fisheries management, insofar as they demonstrate that skipper skill may contribute significantly to variation in catch per unit effort and therefore should be taken into account both in the context of stock assessments, and fleet reduction programmes.

Forecasting Annual Harvests of Atlantic and Gulf Menhaden

AbstractContinuous records of annual landings and fishing effort exist in the Atlantic purse‐seine fishery for Atlantic menhaden Brevoortia tyrannus since 1940 and the Gulf of Mexico fishery for Gulf menhaden B. patronus since 1946. Currently, year‐ahead forecasts of landings from these species‐specific fisheries separated by the Florida peninsula are provided to the industry by means of multiple‐linear‐regression models that relate landings and effort over the data series. Here, we compare three methods for this purpose—multiple regression, time series, and artificial neural networks—to determine whether forecast accuracy can be increased. Best‐fit models were developed with each method for each fishery, and then 10‐year retrospective analyses of 1‐year‐ahead catch forecasts were compared among the three methods. In general, multiple‐regression and artificial neural network models were similar in their fit to the data series and both were better than time series models, judging from the Akaike information criterion, the correlation between observed and predicted catches, the mean prediction error, and the root mean square error of prediction. A 10‐year retrospective analysis (1993–2002) of 1‐year‐ahead catch forecasts indicates that the three methods provided similar within‐stock mean absolute forecast errors (19–21% in the Atlantic and 15–20% in the Gulf), with generally better forecasts for the Gulf fishery. Overall, multiple‐regression and artificial neural network models provide lower average catch forecast errors and better fits to the fishery data, whereas similar forecast errors are provided by a univariate time series model (autoregressive integrated moving average model) in the Atlantic and a multivariate time series model (state space model) in the Gulf.

Population Consumption of Fish and Invertebrate Prey by Striped Bass (Morone saxatilis) from Coastal Waters of Northern Massachusetts, USA

Seasonal, age-class, and population-level changes in diet and consumption demand of prey by striped bass residing in coastal waters of northern Massachusetts were investigated to determine their potential predatory impact on ecologically- and economically-important prey species. Most consumption by individual striped bass of ages 3–8 came from crustaceans and fish. More crusta ceans (50–78% of total consumption) than fish were consumed during June–July, while more fish (52–88% of total consumption) than crustaceans were consumed during August–September. Rock crabs Cancer irroratus and American lobsters Homarus americanus became more important to the production of striped bass as bass aged, but Atlantic menhaden Brevoortia tyrannus became less important. Together, the biomass of prey consumed by all age-classes in 2000 totaled over 5 575 t. Atlantic menhaden accounted for 29% of the total biomass consumed, followed by rock crabs (18%), American lobster (11%), and Atlantic herring Clupea harengus (3%). On a numerical basis, striped bass consumed seasonally over 3, 1 940, and 965 times the numbers of lobsters, rock crabs, and menhaden, respectively, taken annually by regional and statewide fisheries, suggesting striped bass may exert considerable predation pressure on these prey populations.

Associations between fish health and Pfiesteria spp. in Chesapeake Bay and mid-Atlantic estuaries

In response to concerns that there may be an association between harmful algal bloom (HAB) species and fish health, including the widespread use of fish health as one indicator of a possible HAB warranting further investigation, evidence for such an association was evaluated in Chesapeake Bay and other mid-Atlantic estuaries (1999–2001). A statistical approach was used, without invoking causality, to test whether there is an association between the prevalence of externally-visible lesions in fish populations above background levels and the presence of Pfiesteria spp. in co-located water and fish samples. Externally visible anomalies (e.g. ulcers, necrosis, parasites, etc.) were recorded for Atlantic menhaden ( Brevoortia tyrannus) and all other fish collected. Polymerase chain reaction (PCR) techniques were used to test for the presence of Pfiesteria spp. in water samples collected at routine and rapid response sampling events. No actively toxic Pfiesteria was found during this study. Fine-scale (within a given sample site) and broad-scale (estuary-wide sampling) comparisons showed positive associations between externally-visible fish lesions in menhaden populations and the presence of Pfiesteria spp. in co-located samples. Logistic regression modeling of Pfiesteria detection probabilities as a function of prevalence of menhaden with lesions was significant ( P = 0.0096). Reductions in the false positive (tests indicating Pfiesteria presence when its absent) and false negative (tests indicating Pfiesteria is absent when it is actually present) rates occurred when the minimum sample size threshold increased from 1 to 30 fish ( P = 0.003–0.001). This association served as a useful field indicator of potential HAB activity that could warrant further field investigation and testing.

Comparison of Atlantic menhaden gels from surimi processed by acid or alkaline solubilization

Heat-induced gelling abilities of surimis prepared by pH shifting (isoelectric precipitation following acid (AC) or alkaline (AL) solubilization) were compared to that of conventionally washed (CW) surimi. Greater endogenous transglutaminase activity (evidenced as enhanced strength of cooked gels subjected to 30–40 °C preincubation) was measured for CW and AL surimi than for AC surimi (all at pH 7). Upon addition of microbial transglutaminase (MTGase), increased crosslinking of myosin heavy chain and gel strengthening during 30–40 °C preincubation were apparent for all three types of surimi, most markedly in CW and AL surimi. Salt addition improved CW gels most, but seemed to adversely affect MTGase activity in AC and AL surimi. AC and AL surimi gels were of lower whiteness than were CW surimi gels.