Harvest in walleye Sander vitreus fisheries is size-selective and could influence phenotypic traits of spawners; however, contributions of individual spawners to recruitment are unknown. We used parentage analyses using single nucleotide polymorphisms to test whether parental traits were related to the probability of offspring survival in Escanaba Lake, Wisconsin. From 2017 to 2020, 1339 adults and 1138 juveniles were genotyped and 66% of the offspring were assigned to at least one parent. Logistic regression indicated the probability of reproductive success (survival of age-0 to first fall) was positively (but weakly) related to total length and growth rate in females, but not age. No traits analyzed were related to reproductive success for males. Our analysis identified the model with the predictors' growth rate and year for females and the models with year and age and year for males as the most likely models to explain variation in reproductive success. Our findings indicate that interannual variation (i.e., environmental conditions) likely plays a key role in determining the probability of reproductive success in this population and provide limited support that female age, length, and growth rate influence recruitment.

Objective: The objective of this study was to evaluate stocking success of Walleye Sander vitreus in lakes and reservoirs across the Midwestern United States to inform stocking practices for state agencies. Demand for Walleye stocking may increase if climate change limits the potential for natural recruitment in lakes. Consequently, the strategic distribution of Walleye stocking may maximize fishing opportunities. Methods: We synthesized data from 2226 Walleye fry and fingerling stocking events on 653 lakes in the Midwestern United States and used random forest algorithms and mixed-effects linear models to identify abiotic and biotic factors related to Walleye stocking success. Result: Latitude and year explained relatively little variation in stocking success compared to within-lake variation. Relative abundance of Largemouth Bass Micropterus nigricans was an important indicator of Walleye stocking success for fry and fingerlings, with stocking success generally decreasing with increased bass abundance. There was an interaction between lake surface area and growing degree-days, as large lakes (>2500 ha) seemed to be more conducive to Walleye stocking success regardless of growing degree-days. The models that we developed did not accurately predict exact levels of Walleye stocking success but were 92-94% accurate in predicting whether the stocking success of both fry and fingerlings would be at or above the 50th percentile. Conclusion: These findings may help to inform the management and stocking allocation of Walleye and suggest that future increases in Largemouth Bass abundance and growing degree-days could limit the effectiveness of stocking in some lakes.

Aquaculture production is projected to surpass wild-capture fisheries as the primary source of aquatic animal protein in the near future. Farmed shrimp—which are amongst the most valuable aquaculture commodities—are raised predominantly in Southeast Asia and Latin America in a variety of production systems, spanning from extensive to intensive farming. Shrimp aquaculture has been widely criticized for causing mangrove forest degradation and loss, leading to calls for more sustainable aquaculture approaches that protect mangroves. Here we examine an approach promoted as more sustainable—integrated mangrove aquaculture (IMA): a type of farming where mangroves are planted in or alongside shrimp ponds. We argue that mangroves within IMA shrimp systems provide biodiversity and ecosystem functions and services that are, at best, compromised, especially when compared to intact mangrove forests. Given the rapid adoption of IMA approaches, including advocacy for uptake from many governments and non-governmental organizations, there is an urgent need to ensure that these and other aquaculture systems do not result in any conversion of intact mangrove ecosystems into aquaculture ponds, and to identify any benefits (or lack thereof) provided by IMA systems. The increasing adoption of IMA may offer false promises for managing trade-offs between increasing aquaculture productivity and mangrove forest conservation.

Elemental profiling is being explored as a traceability tool in many seafood products. However, the extent that elemental profiling can be used at finer geographical scales in cultured shrimp is unknown. Additionally, few studies have included multiple species in the same discriminant models, which would be useful in applications where one species is common, and the other is not. Here, elemental profiling was used to discern the provenance of black tiger shrimp Penaeus monodon and whiteleg shrimp Litopenaeus vannamei from the regions of North Kalimantan, Sulawesi Seletan, and Aceh in Indonesia. ICP-MS was used to determine elemental concentrations of 41 elements in shrimp muscle tissue and was the basis for multivariate and univariate statistical analyses. A MANOVA showed that multivariate differences exist in regions and between species of shrimp sampled. Univariate comparisons were utilized after the significance of the MANOVA and showed that 19 of the 24 elements above detection limits had significant differences. Classification via random forest was used to access the ability to discern, region, species, and region × species group combinations. The lowest model accuracy was the region × species combinations at 78.9%, while the highest accuracy was species irrespective of geographical origin at 93.59%. Elements that were routinely important in classification included As, B, Ba, Li, Na, Rb, Se, and Zn. Elemental profiles of white leg shrimp and black tiger shrimp are varied and potentially should not be used in the same classification models. Altogether, these results suggest that elemental profiling of farmed shrimp at finer geographic scales needs refinement as a traceability tool.

AbstractEngineering design studies and financial feasibility assessments were made for construction, maintenance, equipment, operations, loan requirement, shrimp sales and predicted cash flows for simulated transformations of extensive shrimp farms to intensive shrimp farms in the Mekong Delta, Vietnam. Farms with less than 2.8 ha of feed‐based, aerated production ponds would not be profitable at shrimp yields less than 5 t/ha/year. Profit projections increased in response to greater production area on farms and larger annual pond yields. Farms with 6 ha or more of production ponds and yields of 10 t/ha/year or more had the best profit potential. Greater profitability at higher production intensity resulted from a reduction in the labour cost/product weight ratio as yield per unit area increased. Transformation from extensive to intensive farms would allow greater shrimp production, increase worker income and lessen land and water use. Environmental benefits would include a reduction in sediment starvation of the Mekong Delta, and the option to restore some of the several hundred thousand hectares of mangrove area severely degraded by extensive shrimp farming. These two improvements would be of benefit in retarding erosion along the Mekong Delta coastline. The possibility of intensification and consolidation of the shrimp farming area in the Mekong Delta deserves further consideration.

Globally, shrimp farms occupied an estimated 3.490 million hectares (Mha) of land and operated 2.426 Mha of production ponds in 2018. Extensive shrimp farms used 1.804 Mha of farm area (1.377 Mha of production ponds), but produced 11.4% of global shrimp production. An estimated 1.718 Mha of land was required to produce ingredients for feeds used in semi-intensive and intensive shrimp farming, bringing total land use to 5.160 Mha. Extensive production is located in the intertidal zone and much of this land formerly was or still is in mangrove areas. Expansion of shrimp farms into mangrove areas has slowed. Mangrove areas are inferior sites for shrimp farms, and governments have imposed stricter regulations to protect mangroves. Shrimp farming in mangrove areas is unnecessary to supply the global shrimp demand. Scenarios for increasing global shrimp production without further increase in shrimp farm area are presented. But, if the demand for shrimp continues to increase, it will be impossible to freeze the total land footprint for farmed shrimp, because the land needed for feed presently is roughly equal to the direct land use for shrimp farms. Direct land use for farms can be frozen through greater production pond yields.

Commercial processing is potentially a confounding factor for elemental profiling in shrimp. Here, two sets of paired samples were collected pre/post-processing from the same farms; one set from Thailand (n = 15) and one from Ecuador (n = 19). The samples from Ecuador were subjected to a meta-bisulfite bath as part of the processing regimen while the samples from Thailand were subjected to a salt bath. The elemental concentrations were determined via ICM-MS. Elements reported are of Al, As, Ba, Ca, Ce, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Nd, Ni, Rb, Se, Sr, Y, and Zn. Elements from samples in Ecuador were unaffected by the processing regimen (MATS = 15.47, p = 0.3), but samples from Thailand (MATS = 766.29, p = < 0.001) were. The pre/postprocessing samples were classified to country of origin with a training model of samples from shrimp farms in five countries. Samples that were post-processing were less accurately classified (58 % vs. 68 % accuracy) compared to pre-processed samples. Samples from Ecuador had high fidelity regardless of processing while the samples from Thailand were less accurately classified. This study shows processing can alter the elemental profile in shrimp muscle tissue, and may impact the accuracy of classification.

The contribution of aquatic animal protein to the global, animal-source protein supply and the relative importance of aquaculture to capture fisheries in supplying this protein is relevant in assessments and decisions related to the future of aquatic food production and its security. Meat of terrestrial animals, milk, and eggs resulted in 76,966 Kt crude protein compared with 13,950 Kt or 15.3% from aquatic animals in 2018.While aquaculture produced a greater tonnage of aquatic animals, capture fisheries resulted in 7,135 Kt crude protein while aquaculture yielded 6,815 Kt. Capture fisheries production has not increased in the past two decades, and aquaculture production must increase to assure the growing demand for fisheries products by a larger and more affluent population. We estimated based on status quo consumption, that aquaculture production would need to increase from 82,087 Kt in 2018 to 129,000 Kt by 2050 to meet the demand of the greater population. About two-thirds of finfish and crustacean production by aquaculture is feed-based, and feeds for these species include fishmeal and fish oil as ingredients. Aquaculture feeds require a major portion of the global supply of fishmeal and fish oil. An estimated 71.0% of fishmeal and 73.9% of fish oil are made from the catch with the rest coming from aquatic animal processing waste. The catch of small, pelagic fish from the ocean is not predicted to increase in the future. Aquaculture should reduce its fishmeal and oil use to lessen its dependency on small wild fish important to the integrity of marine food webs and food security for the poor in many coastal areas. Fishmeal and fish oil shortages for use in aquaculture feed will result in a limit on production in the future if goals to lessen their use in feeds are not met.

BACKGROUND:Elemental profiling is a tool that has been proposed to improve the traceability of seafood products. Small sources of variation can affect the outcome of elemental profiling and therefore pose to lower the overall accuracy of analyses. Here, we investigate two potential sources of variation through three experiments: laboratory variation (intra-, interlaboratory variation, and tissue matrix) and tissue variation.METHODS AND RESULTS:Samples of whitleleg shrimp (Litopenaeus vannamei) were obtained from 20 farms in Ecuador and two farms in Alabama to be analyzed. In the first experiment of the study, samples from Ecuador were analyzed at three different laboratories and compared. Two out of the five elements reported were statistically different across the three laboratories (Cu and Se). In the second experiment, the effect of tissue matrix (ground vs whole tissue during acid digestion) was investigated. Altogether, five out of 29 elements analyzed were statistically different. In the third experiment, samples from two farms in Alabama were analyzed to understand the variation in element concentrations in different tissues (head on shell on (HOSO), headless shell on (HLSO), headless peeled (PLD) and headless peeled and deveined (PLDV)). Elemental concentrations varied across tissues, and patterns in elemental concentrations were site specific. The samples from the two farms were analyzed with a Random Forest classification model to site x tissue groupings with 94% accuracy.CONCLUSION:The result of this study highlights the following: 1. Consistency in laboratory analysis important in studies that involve element concentrations, as minor differences in methodology can propagate as significant differences in results. 2. In shrimp, elements are compartmentalized in different tissues and elemental profiling should consistently use the same type of tissue.

Shrimp are an important and valuable commodity for aquaculture that are widely traded internationally. Widespread antibiotic use has been documented in shrimp farming and is a common source of criticism of aquaculture products. Additionally, previous reports have found some evidence of antibiotic residues in shrimp samples obtained from retail stores in the United States, which is a concern for consumers. To further understand the prevalence of antibiotics in retail shrimp in the United States, shrimp samples obtained from grocery stores across 16 states were analyzed for 74 antibiotic compounds/metabolites at a commercial laboratory. 68 samples were analyzed for a multiclass antibiotic panel which included 66 antibiotics while a subset of 15 samples were analyzed for β-lactam antibiotics, Nitrofurans, and Oxytetracycline. Samples were obtained that were labeled as being from major production countries, including India, Indonesia, Thailand, and Vietnam. No detectable antibiotic residues were found in this survey in any samples. This is contrary to previous findings in frozen shrimp analyzed for antibiotics, which typically report low levels of the prevalence of antibiotics.

The inclusion of feeding effectors in plant-based diets is a strategy to accelerate feed detection and consumption by shrimp. This study evaluated the effect of krill meal (KM), krill oil (KO) and fish hydrolysate (FH) addition to a soybean-based diet on feeding behavior and growth of Litopenaeus vannamei. Ten diets (360 g/kg crude protein) were formulated including FH, KM and KO at 0, 10, 20 and 40 g/kg levels named as: Basal (0); FH10 (10 g/kg fish hydrolysate), FH20 (20 g/kg fish hydrolysate), FH40 (40 g/kg fish hydrolysate); KM1 (10 g/kg krill meal), KM20 (20 g/kg krill meal), KM40 (40 g/kg krill meal); KO10 (10 g/kg krill oil), KO20 (20 g/kg krill oil) and KO40 (40 g/kg krill oil). A growth trial was performed using twenty shrimp (0.15 +/- 0.01 g) stocked per 100 L glass aquaria (four replicates/diet) in an indoor clear water recirculation system (4.2 ppt, 28 degrees C). Animals were fed the experimental diets four times a day for six weeks. At the end of the trial all animals were counted and weighted. Following, 300 animals (3.93 +/- 0.35 g) were aleatory selected and transferred back to the system (10 shrimp/aquaria). Three replicates were used per treatment (ten diets) for feed intake and acoustic feeding behavior analysis. The food consumption and feeding activity sounds were recorded simultaneously in 30 min intervals during five consecutive days. All feeding effectors at the inclusion levels tested significantly increased L. vannamei food consumption and the passive acoustic monitoring indicated that shrimp ate faster and for longer periods of time. Food consumption was significantly higher in the treatments KM20, KM40 and KO40. The addition of feeding effectors also enhanced shrimp growth performance and significantly better values of biomass, final weight, and food conversion ratio were observed in the treatment KM40. Weight gain (%) was significantly improved only in shrimp offered KM40, KO20 and KO40 diets. It is concluded that KM, KO and FH can stimulate food consumption of soy-based diet by L. vannamei from 10 g/kg addition while the amount of food consumed and growth has been shown to be in general dose-related, although in a different way, for each type of feeding effector.

Shrimp are one of the fastest growing commodities in aquaculture and have a considerable land footprint. Here, we explored the impact of utilizing different production methods (extensive vs intensive) for expanding shrimp production on the cumulative land footprint of shrimp aquaculture. A meta-analytic approach was utilized to simultaneously estimate model coefficients to explore three relationships: production intensity and total land burden, production intensity and the proportion of land at the farm, and production intensity and the farmland burden. A literature review was conducted and a total of 7 datasets, 22 subsets, and 973 individual farms were included in this study. The global models were as follows: model 1 -> ln (total land burden) = 0.1165-0.3863 * ln (production intensity), model 2 -> proportion of direct (farm) land use:total land use = 0.7592-0.1737 * ln (production intensity), model 3 -> ln (direct land use) = 0.1991-0.9674 * ln (production intensity). Production expansion was modeled under different scenarios. The most land intensive projections involved using only extensive systems to increase production when compared to a business-as-usual scenario. The least land intensive scenario involved utilizing intensive systems. A scenario where farmland was not expanded used 17% less land and 28% less land to produce 7.5 and 10 million tons of shrimp, respectively, when compared to business-asusual scenarios. These estimates are limited by uncertainty in shrimp feed composition but demonstrate the effect of production intensity on the overall land footprint of shrimp production.

A survey of 101 shrimp farms in Ecuador revealed that the average annual shrimp yield based on production pond water surface area was 7.03 +/- 0.93 (SE) t/ha/year. The range in annual yield among the five provinces with shrimp farms was 3.67 +/- 0.71 to 11.95 +/- 5.56 t/ha year, respectively. Averages for total land, water, and energy use were 0.54 +/- 0.01 ha/t shrimp, 76,817 +/- 6,330 m(3)/t shrimp, and 61.2 +/- 4.2 GJ/t shrimp, respectively. Average wild fish use for fish meal and fish oil included in feed was 0.65 +/- 0.02 t/t shrimp. One-fourth of land use was land embodied in feed. Nearly 80% of total water use was incurred for exchanging water. Eighty-seven of the farms practiced daily water exchange at an average rate of 8.5% pond volume per day (range 0.7-30%). Pumping water at all farms and mechanical aeration at 47 of the farms were the major direct energy uses. About half of the total energy use was embodied, and roughly half of the embodied energy was in feed.

The physical characteristics and leaching rates of water-soluble compounds from shrimp feeds are major considerations in nutrient delivery. Yet, there is limited information on nutrient leaching from feeds or the mechanisms to minimize leaching. This study evaluated the efficacy of various coating agents on the physical characteristics and leaching of nutrients from commercial feeds forLitopenaeus vannamei. A series of diets were top coated with two lipid sources (fish or stearin oil) and two additives to the oil (5% wax or gelatin) at three levels (0, 1.5, and 3%). Physical characteristics and leaching of water-soluble compounds were then characterized. The reduction of leaching was seen with the diets that were top coated with 1.5 or 3% oil, which significantly decreased the leaching of phenylalanine (Phe) after 30 min and 60 min of immersion. Adding 1.5 and 3% oil coating significantly decreased the pellet durability index. Adding gelatin as an additive to the oil significantly slowed sinking velocity and improved water stability and the pellet durability index of the diets. In all, results demonstrated that coating 1.5 or 3% fish or stearin oil decreases the leaching rate. Supplementing 5% gelatin in the coating material for diets can improve the performance of the diets.

Aquaculture production is an important part of the global food supply and has equaled or surpassed fisheries production as the main source of aquatic foods. Aquaculture is a resource intensive practice that can use large amounts of land, water, energy, and cause pollution and degradation to the local environment. Intensive production practices have been criticized in the past for causing environmental harm; however recent studies have suggested that resource use may decrease with increasing production intensities at the farm level. Here we used a conceptual farm to access the impact of a few key production parameters on land, water, and energy use. A series of calculations were conducted at various production intensities with modifications made to the type of feed used and water exchange rate. The resulting relationships were then modeled with production intensity. Additionally, the effect of various feedstuffs on embodied resource coefficients was examined through varying protein and carbohydrate feedstuffs. Land and water use were found to have an asymptotic relationship with production intensity, with the most important factor in land use being production intensity and the most important factor in water use being the water exchange rate. Energy use was found to be higher with a diet that has fish meal as a protein source and at higher water exchange rates. The most land intensive diets used for shrimp contained high fish meal with rice as carbohydrate feedstuffs (0.550 ha/tonne). The most water intensive diet was no fish meal with corn as a carbohydrate (1863 m3/tonne), and the most energy intensive diet was high fish meal with corn as a carbohydrate (11.73 GJ/tonne). The results herein suggest that intensifying shrimp aquaculture could save resources based on per tonne of production basis.

A 70-day trial was conducted to evaluate the effect of dietary protein matrix (soybean meal or poultry byproduct meal-PBM) on taurine efficacy and retention in juvenile white seabass Atractoscion nobilis. Diets were formulated to contain 40% protein and 12% lipids with taurine supplementation ranging from 0 to 1.37% taurine. Fish were fed 4–8% body weight/day over the course of the trial. Growth performance metrics and taurine retention in fish were measured and compared using a linear regression model with diet type as covariates (growth parameters) or a quadratic model with diet type as covariates (taurine retention and deposition). Fish fed diets with soy proteins had lower percent gain, survival, feed fed/fish, and thermal-unit growth coefficients (TGC) at similar levels of taurine inclusion when compared to diets with primarily PBM as the protein source. Taurine level was positively correlated with mean final weight, weight gain, percent gain, TGC of fish regardless of diet, and negatively correlated with FCR regardless of the diet. A taurine requirement based on whole-body deposition was calculated to be 1.18%, 1.21%, and 1.03% for all diets, PBM diets, and soy diets, respectively. These results demonstrate that the protein source did not influence the taurine requirement and suggest that taurine deficiencies are not the driver of lower TGC or survival in white seabass fed diets with soy, and that other factors warrant investigation.

Four growth trials were conducted to evaluate the effects of fishmeal replacement with various levels of soybean meal (SBM) and poultry byproduct meal (PBM) on growth performance in practical diets for juvenile and sub-adult red snapper, Lutjanus campechanus. In addition, the need for taurine and palatability enhancement (krill meal) were evaluated in the high SBM, low fishmeal diet. Across the trials, ten diets were formulated to contain 36% protein and 10% lipids. All diets except for one included a taurine supplement of 1%. A supplement of 5% krill meal was added as an attractant to one of the low fishmeal and high SBM diets to explore potential palatability issues associated with plant-based proteins. No statistically significant differences were found between the performance of the basal diet and the PBM replacement diets, indicating that PBM is a suitable replacement for fishmeal in red snapper diets. On the contrary, a clear negative linear relationship was observed with increasing levels of SBM replacement. The reduced growth performance of high SBM inclusion diets is unlikely to be due to palatability issues, as no significant difference was observed between the performance of the high SBM diet with krill meal and an identical diet without krill meal. The significant reduction in growth observed in snapper fed a diet lacking a taurine supplement indicates that red snapper have a taurine requirement that is limiting at low (0.2%) levels. Gut samples were taken from fish that received the SBM diets to determine if reduced growth performance could be attributed to inflammation. However, no statistically significant difference was observed, indicating that reduced growth was not necessarily the result of a hypersensitivity reaction. Further investigation will be necessary to determine the optimal taurine requirement and required dietary supplements to improve the performance of low fishmeal feed formulations.

Three trials were conducted to evaluate the performances of red snapper, Lutjanus campechanus, in low salinities. The median lethal concentration (96 h LC50) of salinity was determined by trimmed Spearman-Karber method using survival data of fish (18.9 ± 0.2 g) collected after 96 h from acclimation to 2, 4, 8, and 32 ppt salinities in 800 L tanks (n = 3), while the serum osmolality of fish (74.1 ± 3.9 g) was determined after 48 h from acclimation to 6, 8, 16, 24, and 32 ppt salinities in 150 L tanks (n = 3). The growth trial was conducted for 6 weeks in 800 L tanks to determine the growth and survival of fish (18.8 ± 0.2 g) at 8 ppt salinity compared to the control (32 ppt salinity). At the conclusion, the isosmotic point of fish was estimated as 357.2 mmol/kg (correspond to 11.0 ppt salinity), while the 96 h LC50 was estimated as 5.65 ppt salinity. No significant differences were noted for survival and FCR of fish reared in 8 and 32 ppt salinities. However, growth was significantly lower in fish reared in 8 ppt salinity compared to the fish reared in 32 ppt salinity. The reduced growth could be, at least partially, due to the increased osmoregulatory energy expenditure at lower salinities.