Stomach content analyses of mullet from the Swartkops estuary

The stomach content of four species of mullet (Mugil cephalus, Liza dumerili, Liza richardsonii and Liza tricuspidens), was analyzed. The nature of the stomach content gave some indication of the areas in which each species of mullet had been feeding, the type of substratum from which each had been feeding and the diatom species which each ate

Stomach content analyses of Pomadasys commersonni from the Swartkops Estuary (Pisces: Pomadasyidae)

No Abstrac

Apparatus for the automatic determination of oxygen consumption in fish

An apparatus is described which permits the automatic determination of the oxygen consumption of three fish and a control for 24 hours per day. This is made possible by an electrical control system operating four three-way valves which allow water from one of four respiration chambers at a time to flow past an oxygen electrode for quarter-hour periods. These values are registered successively on a recorder

Structures associated with feeding in three broad-mouthed, benthic fish groups

The flatheads, toadfishes, and goosefishes discussed here hold certain features in common. All are bottom-living forms with depressed head areas and broad gapes, and all eat large food items: fishes and/or crabs. All have developed structural specializations in association with this diet. The three groups are at most distantly related, and their feeding specializations are different and have evolved from different bases. In flatheads the combination of large food items and depressed head regions seems to have led to the separation of the two halves of the pelvic girdle, a feature in which they differ from their scorpaenoid relatives. Toadfish peculiarities associated with feeding are various but most notable in those that pass crabs they eat through the gape and into the mouth. Goosefish feeding is centered around the use of a lure to attract prey to within striking distance. The three fish groups are discussed separately, but their feeding structures are compared to one another in the final section of the paper.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42639/1/10641_2004_Article_BF00005053.pd

Seasonal abundance, distribution and catch per unit effort of fishes in the Krom estuary, South Africa

No Abstract

Feeding ecology of major carnivorous fish from four eastern Cape estuaries

No Abstract

Seasonal abundance, distribution, and catch per unit effort using gill-nets, of fishes in the Sundays estuary

Catch per unit effort was obtained for the fish of the Sundays estuary by means of gill-netting. Fifty-five gill-net catches were made in which 1258 fish were caught in the mouth, middle and upper reaches of the estuary. Sea catfish, Tachysurus feliceps dominated catches numerically and kob Argyrosomus hololepidotus In terms of weight (31% of total). CPUE was 21 kg/standard net. Mean body weight of fish was 894 g. It seems that the food web in the Sundays estuary is based largely upon phytoplankton and dependent zooplankton grazers

Fish abundance and distribution in the Gamtoos estuary with notes on the effect of floods

No Abstract

The effects of river flooding on the fish populations of two eastern Cape Estuaries

The effect of river flooding during July and August 1979 on fish populations in two eastern Cape estuaries is compared. It is shown that floods of varying intensity occur regularly in these estuaries. Fish populations in the two estuaries, namely the Swartkops and the Sundays, were differently affected: members of the family Mugilidae increased in numbers in the Swartkops estuary after the floods but decreased to insignificant numbers in catches in the Sundays estuary for a number of months after the floods. It is postulated that mud and silt which are deposited in the Swartkops during the flood serve as a food source for the mullet whereas the rich surface benthos layer of a channel-like estuary like the Sundays is washed away by heavy floods

Analysis of anglers' catch data from the Swartkops Estuary

An analysis of anglers' catch data from 1972-1978 revealed that the spotted grunter Pomadasys commersonni is the most abundant angling species in the Swartkops estuary (83% of mass and 87% of numbers). It is followed by Lithognathus lithognathus, Argyrosomus hololepidotus and Lichia amia. During the early part of this century L. lithognathus was the most abundant species in the estuary followed by A. hololepidotus, P. commersonni and Pomatomus saltatrix. Various factors such as food availability, reproduction and climatic conditions which could be responsible for seasonality of catches are discussed