Food habits of California Sea Lions (Zalophus californianus) and their impact on Salmonid Fisheries in Monterey Bay, California

In the ocean commercial troll and recreational salmon fishery in Monterey Bay California, California sea lions (Zalophus califomianus) will swim near or follow fishing boats and will depredate fish once hooked. The objectives of the study were to determine the percentage of salmon taken by pinnipeds in commercial and recreational fisheries, identify relative importance of prey items seasonally consumed by sea lions, and determine the proportion of salmonids in the sea lion diet on a seasonal basis. From April 1997 through September 1998, 1041 hours of onboard and dockside surveys of the commercial and recreational salmon fisheries were conducted at the three ports in Monterey Bay, California. Sea lions depreadated 7.9 % of the fish hooked in the commercial fishery in 1997 and 28.6 % in 1998,8.4 % (1997) and 18.3 % (1998) of the CPFV fishery, and 15.6 % (1997) and 17.5 % (1998) of the private skiff fishery. Increased depredation rates in both the commercial and recreational salmon fisheries in 1998 were most likely the result of the large EI Nino Southern Oscillation event that occurred in 1997-1998 during which a greater number of sea lions were present in central California. Prey hardparts identified in sea lion fecal samples collected in Monterey Bay indicated that schooling fishes were the predominant prey fish species, such as market squid (Loligo opalescens), Pacific sardine (Sardinops caeruleus), northern anchovy (Engraulis mordax), and rockfish (Sebastes sp.). Sea lions consumed similar prey species in the summer and fall 1997, winter 1997-98, and spring 1998 (PSI> 70.0) with market squid and northern anchovy being the dominant prey species. However, prey composition changed significantly during the summer 1998 and fall 1998 (PSI < 46.0) because of the increased importance of sardine and rockfish in the diet and the decreased importance of market squid. This report does not intend to imply that salmonids are not a prey species for pinnipeds in the Monterey Bay region, but highlights the difficulties encountered in establishing the role of salmonids in the pinniped diet when analyzing fecal samples. (PDF contains 38 pages).

Food habits as an ecological partitioning mechanism in the nearshore rockfishes (Sebastes) of Carmel Bay, California

In the kelp forests of Carmel Bay there are six common rockfishes (Sebastes). Three are pelagic (S. serranoides, S. mystinus, and S. melanops) and two are demersal (S. chrysomelas and S. carnatus). The sixth (S. atrovirens) is generally found a few meters above the sea floor. The pelagic rockfishes which are spatially overlapping have different feeding habits. All rockfishes except S. mystinus utilize juvenile rockfishes as their primary food source during the upwelling season. Throughout the non-upwelling season, most species consume invertebrate prey. The pelagic rockfishes have shorter maxillary bones and longer gill rakers than their demersal congeners, both specializations for taking smaller prey. They also have longer intestines, enabling them to utilize less digestable foods. S. mystinus, which has the longest intestine, may be able to use algae as a food source. Fat reserves are accumulated from July through October, when prey is most abundant. Fat is depleted throughout the rest of the year as food becomes scarce and development of sexual organs takes place. Gonad development occurs from November through February for all species except S. atrovirens.

Food habits and dietary variability of pelagic nekton off Oregon and Washington, 1979-1984

The food habits of 20 species of pelagic nekton were investigated from collections made with small-mesh purse seines from 1979-84 off Washington and Oregon. Four species (spiny dogfish, Squalus acanthias; soupfin shark, Galeorhinus zyopterus; blue shark, Prionace glauca; and cutthroat trout, Salmo clarki) were mainly piscivorous. Six species (coho salmon, Oncorhynchus kisutch; chinook salmon, O. tshawytscha; black rockfish, Sebastes melanops; yellowtail rockfish, S. f1avidus; sablefish, Anoplopoma fimbria; and jack mackerel, Trachurus symmetricus) consumed both nektonic and planktonic organisms. The remaining species (market squid, Loligo opalescens; American shad, Alosa sapidissima; Pacific herring, Clupea harengus pallasi; northern anchovy, Engraulis mordax; pink salmon, O. gorbuscha; surf smelt, Hypomesus pretiosus; Pacific hake, Merluccius productus; Pacific saury, Cololabis saira; Pacific mackerel, Scomber japonicus; and medusafish, Icichthys lockingtom) were primarily planktonic feeders. There were substantial interannual, seasonal, and geographic variations in the diets of several species due primarily to changes in prey availability. Juvenile salmonids were not commonly consumed by this assemblage of fishes (PDF file contains 36 pages.)

Analysis of Body Composition and Food Habits of Spanish Celiac Women

The purpose of the present work was both to analyze composition of Spanish celiac women and to study the food habits and gluten-free diet of these celiac patients, in order to determine whether they achieve a balanced and healthy diet as well as to highlight nutritional qualitative and/or quantitative differences. 54 adult celiac women (34 +/- 13 years) took part in the six-month study. Height, weight and body composition were measured. An analysis of energy consumption and of the macronutrient distribution of their diet was carried out. Their fulfillment of micronutrient intake recommendations was verified. Participants showed a Body Mass Index of 21.6 +/- 2.4 kg/m(2). Energy Intake was slightly lower than the Dietary Reference Intakes. Excessive protein apart from over-consumption of fat was observed. More than three quarters of participants consumed meat in excess. Carbohydrate consumption along with that of fiber was below recommended levels. Vitamin D, iron, and iodine had a low percentage of recommendation compliance. In general, participants followed the recommendations of dairy products and fruit intake whereas vegetable consumption was not enough for the vast majority. We conclude that although the diet of celiac women does not differ much from the diet of general population, some considerations, such as reducing fat and protein consumption and increasing fiber intake, must be taken into account.

Food habits of Steller sea lions (Eumetopias jubatus) off Oregon and northern California, 1986–2007

We described the diet of the eastern stock of Steller sea lions (Eumetopias jubatus) from 1416 scat samples collected from five sites in Oregon and northern California from 1986 through 2007. A total of 47 prey types from 30 families were identified. The most common prey was Pacific hake (Merluccius productus), followed by salmonids (Oncorhynchus spp.), skates (Rajidae), Pacific lamprey (Lampetra tridentata), herrings (Clupeidae), rockfish (Sebastes spp.), and northern anchovy (Engraulis mordax). Steller sea lion diet composition varied seasonally, annually, and spatially. Hake and salmonids were the most commonly identified prey in scats collected during the summer (breeding season), whereas hake and skate were most common in the nonbreeding season. Continued research on Steller sea lion diet and foraging behavior in the southern extent of their range is necessary to address issues such as climate change, interaction with competing California sea lions, and predation impacts on valuable or sensitive fish stocks.

Food habits of Atlantic white-sided dolphins (Lagenorhynchus acutus) off the coast of New England

Although the Atlantic white-sided dolphin (Lagenorhynchus acutus) is one of the most common dolphins off New England, little has been documented about its diet in the western North Atlantic Ocean. Current federal protection of marine mammals limits the supply of animals for investigation to those incidentally caught in the nets of commercial fishermen with observers aboard. Stomachs of 62 L. acutus were examined; of these 62 individuals, 28 of them were caught by net and 34 were animals stranded on Cape Cod. Most of the net-caught L. acutus were from the deeper waters of the Gulf of Maine. A single stomach was from the continental slope south of Georges Bank. At least twenty-six fish species and three cephalopod species were eaten. The predominant prey were silver hake (Merluccius bilinearis), spoonarm octopus (Bathypolypus bairdii), and haddock (Melanogrammus aeglefinus). The stomach from a net-caught L. acutus on the continental slope contained 7750 otoliths of the Madeira lanternfish (Ceratoscopelus maderensis). Sand lances (Ammodytes spp.) were the most abundant (541 otoliths) species in the stomachs of stranded L. acutus. Seasonal variation in diet was indicated; pelagic Atlantic herring (Clupea harengus) was the most important prey in summer, but was rare in winter. The average length of fish prey was approximately 200 mm, and the average mantle length of cephalopod prey was approximately 50 mm.

Diet composition and food habits of demersal and pelagic marine fishes from Terengganu waters, east coast of Peninsular Malaysia

Fish stomachs from 18 demersal and pelagic fishes from the coast of Terengganu in Malaysia were examined. The components of the fishes’ diets varied in number, weight, and their frequency of occurrence. The major food items in the stomachs of each species were determined using an Index of Relative Importance. A conceptual food web structure indicates that fish species in the study area can be classified into three predatory groups: (1) predators on largely planktivorous or pelagic species; (2) predators on largely benthophagous or demersal species; and (3) mixed feeders that consume both pelagic and demersal species.

Food habits of two sciaenid fish species (Pseudotolithus typus and Pseudotolithus senegalensis) off Cameroon

Pseudotolithus typus and P. senegalensis (Sciaenidae) sampled off Cameroon Coast, West Africa, have been found to feed mainly on shrimps (Nematoplaemon hastatus and Parapenaeopsis atlantica) and juvenile fish (mostly clupeids). The diet composition is presented and discussed.

The food habits of four kelp-bed rockfishes (Scorpaenidae, Sebastes) off Santa Barbara, California

The diets of four common rockfishes from the kelp beds near Santa Barbara, California, were determined by gut contents analysis, and related to feeding strategies. The guts of one hundred specimens of each species were examined, and the importance of prey evaluated by their frequency of occurrence, numbers, and volumes. The volumes of stomach contents were standardized for the size of specimen. Estimates of overlap in diet between the species were made. Sebastes atrovirens fed primarily on small animals from the kelp canopy, and may have employed a browsing rather than pursuing strategy of feeding. It showed low overlap in diet with the three bottom-dwelling species, S. carnatus, S. chrysomelas, and S. vexillaris, all of which preferred larger types of prey and seemed more like pursuers. The closely related S. carnatus and S. chrysomelas were quite similar in diet, eating primarily medium sized demersal invertebrates, especially crabs and shrimp. S. vexillaris ate fewer crabs and shrimp but more large-sized fish and octopus than the latter two species. Its more active life style indicates that it may react to prey at greater distances and have a larger home range than these species, as has been predicted for pursuers feeding on larger (and rarer) prey.

The food habits of hatchery-produced pond-cultured shad (Alosa sapidissima) reared to a length of two inches

The present study was aimed at determining the food habits of hatchery-produced, pond-cultured shad (Alosa sapidissima) reared to a total length of approximately two inches. More specifically, the objectives were to determine: (1) That point in life at which young shad start to consume food; (2) What type or types of food the young shad consume at the onset of feeding; (3) Food changes, if any, which occur with age and growth in size up to the arbitrarily designated total length of two inches. The plan was that the shad larvae be introduced into an outdoor rearing pond previously fertilized, and that the larvae be dependent upon the plankton for food as they would be under natural conditions.

Food habits of Sowerby's beaked whales (Mesoplodon bidens) taken in the pelagic drift gillnet fishery of the western North Atlantic

We describe the food habits of the Sowerby’s beaked whale (Mesoplodon bidens) from observations of 10 individuals taken as bycatch in the pelagic drift gillnet fishery for Swordfish (Xiphias gladius) in the western North Atlantic and 1 stranded individual from Kennebunk, Maine. The stomachs of 8 bycaught whales were intact and contained prey. The diet of these 8 whales was dominated by meso- and benthopelagic fishes that composed 98.5% of the prey items found in their stomachs and cephalopods that accounted for only 1.5% of the number of prey. Otoliths and jaws representing at least 31 fish taxa from 15 families were present in the stomach contents. Fishes, primarily from the families Moridae (37.9% of prey), Myctophidae (22.9%), Macrouridae (11.2%), and Phycidae (7.2%), were present in all 8 stomachs. Most prey were from 5 fish taxa: Shortbeard Codling (Laemonema barbatulum) accounted for 35.3% of otoliths, Cocco’s Lanternfish (Lobianchia gemellarii) contributed 12.9%, Marlin-spike (Nezumia bairdii) composed 10.8%, lanternfishes (Lampanyctus spp.) accounted for 8.4%; and Longfin Hake (Phycis chesteri) contributed 6.7%. The mean number of otoliths per stomach was 1196 (range: 327–3452). Most of the fish prey found in the stomachs was quite small, ranging in length from 4.0 to 27.7 cm. We conclude that the Sowerby’s beaked whales that we examined in this study fed on large numbers of relatively small meso- and benthopelagic fishes that are abundant along the slope and shelf break of the western North Atlantic.

Food habits and consumption rates of common dolphinfish (Coryphaena hippurus) in the eastern Pacific Ocean

An ecosystem approach to fisheries management requires an understanding of the impact of predatory fishes on the underlying prey resources. Defining trophic connections and measuring rates of food consumption by apex predators lays the groundwork for gaining insight into the role of predators and commercial fisheries in influencing food web structure and ecosystem dynamics.We analyzed the stomach contents of 545 common dolphinfish (Coryphaena hippurus) sampled from 74 sets of tuna purse-seine vessels fishing in the eastern Pacific Ocean (EPO) over a 22-month period. Stomach fullness of these dolphinfish and digestion state of the prey indicated that diel feeding periodicity varied by area and may be related to the digestibility and energy content of the prey. Common dolphinfish in the EPO appear to feed at night, as well as during the daytime. We analyzed prey importance by weight, numbers, and frequency of occurrence for five regions of the EPO. Prey importance varied by area. Flyingfishes, epipelagic cephalopods, tetraodontiform fishes, several mesopelagic fishes, Auxis spp., and gempylid fishes predominated in the diet. Ratios of prey length to predator length ranged from 0.014 to 0.720. Consumption-rate estimates averaged 5.6% of body weight per day. Stratified by sex, area, and length class, daily rations ranged up to 9.6% for large males and up to 19.8% for small dolphinfish in the east area (0–15°N, 111°W–coastline). Because common dolphinfish exert substantial predation pressure on several important prey groups, we concluded that their feeding ecology provides important clues to the pelagic food web and ecosystem structure in the EPO.

Studies on the food habits of three species of Mastacembelidae

To identify the food habits of three species of Mastacembelidae namely Mastacembelus armatus, Mastacembelus pancalus and Macrognathus aculeatus, the gut content analysis was performed by three methods i.e. occurrence method, points method and index of fullness method. All three species were found to consume prawn, molluscs, insects, earth warm, debris and plant materials. M. armatus and M. pan cal us were found to feed mainly on animal food items and 84.68% of different types of animal food were taken by M. armatus and 62.72% by M. pancalus. M. aculeatus was found to consume 44.86% of different types of animal food items, 53.51% of debris and plant materials which indicated that this fish feeds almost equally on animal and plant food. Analysis of the food habits showed that both M. armatus and M. pancalus are carnivore in nature with higher feeding preference for animal food namely prawn, crabs, fishes, molluscs etc. On the other hand, M. aculeatus is an omnivore in nature feeding almost equally on animal and plant food.

Food habits of Oxygaster bacaila (Ham.) from Kaptai Lake, Bangladesh

Gut contents of 120 Oxygaster bacaila fmm Kaptai Lake were studied. Index of preponderance (IP) indicated that 0. bacaila consumed highest amount of Insects (35.89%) and thus occupied the first position among the food items. Zooplankton (Rmifera and crustacea 31.79%) and the other food items found in the guts were algae (Chlorophyceae, Bacillariophyceae, Euglenophyceae and Cyanophyceae 24.51%). From the analysis of gut contents, this fish might be considered as omnivore as it consumed both animal and plant foods with higher preference for animal food. The feeding intensity of this fish is fairly high. Total length (TL) versus gut length (GL) relationship and their ratio were found to be GL = 0.57663 TLL04801 (r = 0.9963) and TL: GL = l: 0.7086 respectively.