Penaeus Merguiensis De Man Research Articles

A Comparative Study of Some Larval Stages of Penaeus monodon and Penaeus merguiensis (Crustacea : Decapoda) from Indonesia

The nauplius VI, protozoea II and mysis II of Penaeus monodon and P. merguiensis from Indonesian waters have been described and illustrated. The similarities and the differences between the two species have been observed. The comparison between the present study and that by previous authors have been made. Setation on endopod of maxilliped I and maxilliped II of protozoea and mysis stages as specific characters for identification is suggested. Two species of economically important penaeid prawns, Penaeus merguiensis De Man, 1888, and, P. monodon Fabricius, 1798, are among the many penaeids found in Indonesian waters. Although it is well known that their larvae occur in the coastal waters and are often mixed together (Noor-Hamid, 1976), accurate identification of their wild larvae is now possible only for post-larvae and juveniles, and identification at earlier stages is not yet succeeded. Larval stages of these species have already been described by some authors based upon materials from India (Silas et al., 1978) and the Philippines (Motoh, 1979; Motoh & Buri, 1979). Their information is available for identification of these larvae in Indonesian waters to certain extent, but some problems, which are probably related to difference of material andjor accuracy in observation, must be cleared before it is applied to Indonesian materials. In the present paper, larval stages of these two species, especially nauplius VI, protozoea II and mysis II, are described and compared on the basis of specimens reared in the laboratory, paying special attention to the type and number of setae on the appendages. Larvae of two species of penaeid prawns, Penaeus monodon and P. merguiensis, reared from eggs spawned in the laboratory were received from the Brackishwater Aquaculture Development Centre, Jepara. The larvae were preserved in 10% formalin and were used for morphological observation. Dissection of appendages was performed in 10% glycerin and drawings were made with Projectina, a micro photographic and drawing instrument. For each larval stage of the two species, 10 specimens were randomly taken for measurements with a micrometer eyepiece. The identification of substages is based on that used by Motoh (1979). Body lengths of nauplii were measured along the midline from apical to caudal margins, exclud-

The mechanism of food ingestion by the banana prawn,Penaeus merguiensis

Food passed by the chelate pereiopods to the mouthparts of Penaeus merguiensis de Man is propelled dorsally to the mouth through a pre‐oral cavity made up of the setal fringes of the first two pairs of maxillipeds and the two pairs of maxillae. The setal fringes interdigitate and move with a ratchet action. Food is sheared off and crushed by the mandibles, pushed into the oesophagus by the setae on the labrum and prevented from escaping from the mouth by the paragnaths and labrum. In addition to setae, the endopods of the second maxillipeds and the paragnaths have glands the pores of which open on to their surfaces. Non food items are expelled by downward directed movements of the appendages forming the pre‐oral cavity.

Growth of the banana prawn, Penaeus merguiensis De Man, as estimated from tagging studies in the Gulf of Papua

To estimate the growth parameters of the banana prawn, P. merguiensis, a tag-recapture study, using vinyl streamer tags (Floy FTSL-731, was undertaken throughout the northern Gulf of Papua. Recapture data were analysed using Fabens' derivation of the von Bertalanffy growth curve. A differential growth rate was found between male and female banana prawns: L∞ and K values for males were 29.34 mm carapace length (C.L.) and 0.136 per week, and for females 35.34 mm C.L. and 0.117 per week, respectively. The assumptions applied in estimating the parameters by the Fabens method were not invalidated. These prawns were shown to have a smaller maximum size than banana prawns from the Gulf of Carpentaria, and it is proposed that two discrete populations exist.

Maturation and spawning of the banana prawn Penaeusmerguiensis de Man (Crustacea : Penaeidae) in the Gulf of Carpentaria, Australia

Investigation of the reproductive cycles of female Penaeus merguiensis de Man in the Gulf of Carpentaria showed that maturation of ovaries from the stage of vitellogenesis (Stage III) to the ripe condition (Stage IV) and subsequent spawning occur during a single intermoult period. The sequence of events in reproductive and non-reproductive moulting cycles are described. Fecundity varied from ≈100 000 to 450 000 eggs for individuals of 28 to 45 mm carapace length, respectively. Investigation of spawning seasons and spawning areas was based on the use of an index of population fecundity so that the effects of abundance of a spawning population and the relative contribution of various sizes of spawning females on overall egg production could be considered. Spawning occurred generally over the range of the adult distribution with a tendency for more spawning activity in deeper waters. Egg production was markedly seasonal. Greater egg production occurred during spring and autumn in both the southeastern Gulf and the Weipa area, with a dominant autumn peak in the southeastern Gulf and a dominant spring peak at Weipa. Peaks of spawning activity in the Cape Keerweer area were in August, January and April. Maximum peaks of reproductive output do not forecast maximum recruitment of postlarvae to the estuary systems in each area. Possible explanations for this are discussed.

Setal development, moult-staging and ecdysis in the banana prawn Penaeus merguiensis

Specimens of juvenile Penaeus merguiensis de Man (1888) were captured by seine netting from the shores of Cleveland Bay, Townsville, Queensland Australia between February 1980 and November 1981. Accurate determination of moult cycle stage can be achieved rapidly by microsopical examination of setal development in an excised whole pleopod. Four major stages and 5 substages within premoult were clearly defined. The rate of setogenesis varies along the length of a pleopod, precluding the examination of only one specific location on the pleopod for accurate moult cycle staging. The process of ecdysis lasts for no more than 40 s.

The Influence of Temperature and Salinity Upon the Acute Toxicity of Heavy Metals to the Banana Prawn (Penaeus merguiensisde Man)

Abstract Bioassays were conducted to determine the effects of temperature and salinity on the acute toxicity of mercury, copper, cadmium, zinc, nickel and lead to juvenile banana prawns (Penaeus merguiensis de Man). Tests were conducted at all combinations of 35, 30 and 20°C with 36 and 20° salinity over 96 h. The general rank order of metal toxicity was Hg > (Cu, Cd, Zn) > Ni > Pb. The toxicity of all metals increased with increased temperature. This was most noticeable in the high salinity treatments, particularly for copper and zinc. Salinity appeared to influence the toxicity of all metals tested although significant differences were only found for copper and lead at 20°C. At this temperature prawns were markedly more susceptible to both metals in low salinity sea water. The data are compared with lethal concentrations found for other crustaceans and are discussed in relation to existing water quality criteria.

Statolith implantation in the banana prawn Penaeus merguiensis

Specimens of Penaeus merguiensis de Man were captured between February and May 1981 from intertidal creeks and beaches of Cleveland Bay, Townsville, Australia, using a 15 m seine net. The statocyst of P. merguiensis resembles that of other macrurans in that it is a dorsal invagination of the basal antennular segment lined with groups of sensory hairs. The statolith is composed of sand grains implanted by the prawn from the substratum which must be done after every moult. Implantation begins within 90 min of ecdysis and has 3 phases: sifting; digging and finally eye withdrawal which pushes the sand grains into the statocyst chamber.

Osmoregulatory ability and juvenile habitat preference in some penaeid prawns

An investigation was made of the osmoregulation, over a salinity ( S) range 3–50‰, of early juvenile and adult penaeid prawns, whose nursery-ground preferences range from rivers of widely fluctuating salinity (banana prawn Penaeus merguiensis de Man; greasyback prawn Metapenaeus bennettae Racek & Dall) through open estuaries with very occasional low salinities (tiger prawn Penaeus esculentus Haswell) to open bays and lower estuaries with fairly stable high salinities (king prawn, P. plebejus Hesse). Adult banana prawns osmoregulated well between S 15–40‰ with isosmotic point ≈ S 27‰, but could not adapt below S 7 ‰, whereas adult greasyback prawns osmoregulated extensively from S 3–50 ‰ with isosmotic point ≈ S 23 ‰. Adult tiger and king prawns had limited osmoregulatory abilities with isosmotic points ≈ S 30 ‰ and lower lethal limits of ≈ S 10 and 7‰, respectively. Early juveniles of all four species were, however, all highly efficient osmoregulators and the curves of the three Penaeus spp. were almost identical below their isosmotic points, which were appreciably lower than those of the adults. Lower lethal limits were S 3‰ or below. It is concluded that nursery-ground selection by the species is unlikely to be determined by osmoregulatory ability. Possible factors determining nursery-ground selection are discussed.

Food and Feeding Habits of the White Prawn Penaeus merguiensis

Stomach-content analyses revealed that the white prawn Penaeus merguiensis de Man, in the Angsd Bank-Klang Strait waters (Straits of Malacca), feed on a variety of food - depending on the locality and availability of food items. In the nursery ground, newly-arrived pelagic postlarvae are carnivores, feeding largely on copepods. Epibenthic postlarvae and juveniles are carnivorous detriti-vores, consuming mainly organic detritus; they also prey on small animals like foraminiferans, copepods, larval bivalves and brachyuran larvae. In the maturation ground, subadults are detritivorous carnivores, feeding mainly on large crustaceans, like species of Acetes and mysids; in lesser amounts, on organic detritus. In the spawning ground, adults are detritivore-cdrnivores consuming equal amounts organic detritus and a variety of large crustaceans, polychaetes, molluscs and fishes. However, there are indications that the prawn prefer animal food if available. Organic detrltus is considered a food supplement; its utilization as a food source becomes important to the maturing prawn when it assumes a benthic existence.

Structure and function of the third maxillipeds of the banana prawn Penaeus merguiensis

The functions of the third maxilliped of Penaeus merguiensis de Man are described. It has a 6-segmented endopodite which is used in feeding, grooming and possible pheromone reception. In feeding, large pieces of food are gripped by the stout spines on inner borders of the ischia which hold them to the mouth so that particles can be torn off and ingested. All the distal segments have long setae used in grooming chelate pereiopods and the antennules. In mature males there is a tuft of about 300 slender setae at the end of the propus, but its function remains obscure.

Effect of ration size and feeding frequency on the growth and food conversion of juvenile Penaeus merguiensis de Man

When juvenile Penaeus merguiensis were fed four times daily they increased in weight more rapidly and utilized their food more efficiently than when fed once per day. The maximum ration for prawns given a commercial dry pellet was approximately 12.0% of the wet body weight per day and changed very little as the prawns grew from 0.5 to 1.3 g in indoor culture. Food conversion efficiency declined with increasing weight and ration size but the relative loss in efficiency was least when rations were maintained near to the maximum. Evidence is presented for the existence of a negative K-line relationship in P. merguiensis.

Influence of dietary protein and energy on growth, food consumption and food conversion efficiency in Penaeus merguiensis de Man

The requirement of juvenile Penaeus merguiensis for dietary protein and energy was assessed in growth trials performed in indoor recirculation systems using rations based on freeze-dried Mytilus edulis meal. From the results of these experiments evidence was obtained to indicate that the rate of food consumption in this prawn is related to the energy content of the diet. The implications of this are that the protein level required to support maximum growth and optimum protein conversion efficiency are also energy dependent. Optimum protein levels were estimated in the range 34.0–42.0% for diets of energy content 2.9–4.4 kcal/g. A possible scheme relating food consumption, energy production and growth in P. merguiensis is presented.

Effects of Change in Catchability on Sampling of Juvenile and Adolescent Banana Prawns, Penaeus merguiensis de Man

To provide the information necessary for optimizing sampling strategies, the effects of tidal, diurnal, lunar and seasonal cycles on the catchability of juvenile and adolescent banana prawns, P. merguiensis, were examined in the Norman River and in the inshore coastal zone of the Gulf of Carpentaria. A major part of the large variability in catches in both environments was attributable to marked tidal periodicity in catchability. In the river, large catches of juvenile P. merguiensis were taken only at or near the time of low water during both the neap and spring tide periods. Smaller prawns (< 12 mm carapace length) tended to be even more restricted to the time of low water than were larger prawns. This phase shift in catchability of larger prawns was particularly evident in the offshore sampling where large catches of adolescent prawns were made only at high water. Both the number and size of prawns caught also varied considerably with water depth. The reasons for the marked differences in catchability throughout a tidal cycle are not clear, but it is obvious that sampling can be restricted in time, thus providing much more consistent data with a minimum of effort.

Seasonal Migration Patterns of Postlarval and Juvenile Banana Prawns, Penaeus merguiensis de Man, in the Major Rivers of the Gulf of Carpentaria, Australia

Samples of juvenile P. merguiensis taken from 20 major rivers around the Gulf of Carpentaria from 1970 to 1973 showed that the Gulf could be divided into four major areas, each characterized by its own seasonal pattern of postlarval immigration and emigration of juveniles. The main nursery areas for the Gulf, however, are the rivers along the east and south-east coasts (Cape Keerweer to Mornington Island) and the majority of prawns migrate from these rivers during the north-west monsoon period (November to February); the main recruitment into the commercial fishery, there- fore, occurs during a relatively confined period each year. Additional sampling in 1976-77 showed that although there have been recent changes in the temporal distribution of adult prawns as a result of increased fishing pressure, no major change in the temporal pattern of postlarval immigration has resulted. An hypothesis is presented in which the observed geographical differences in the seasonal migration patterns are explained with reference to a basic pattern involving two generations of P. merguiensis each year.

Structure and function of the chelate pereiopods of the banana prawn Penaeus merguiensis

Penaeus merguiensis de Man systematically searches the substratum and removes small particles of food from it using the small chelae of the first three pairs of pereiopods. One or more chelae are used to transfer food particles to the mouth. The propus and dactylus of these limbs bear numerous setae arranged in discrete groups along the length of the segments. The tip of each seta is elaborately sculptured and has a large sub-terminal pore. It is probable that these are chemosensory organs responsible for discriminating edible from non-edible material. Proximal to almost every setal group is a much-branched seta (rarely two) which probably measures the depth to which the chela has been inserted into the substratum. At the articulation of the propus and carpus of the first pereiopod are three groups of differently sculptured setae, whose function is to clean the other chelate pereiopods. An elaborate system of pegs and a ridge on the apposable fringes of the chelae might be a mechano-receptive device with a particle size discriminating function. The ridges merge into opposable terminal denticulate pads whose function is to grasp food and other particles, which may be quite small (10 to 20 μm upwards).

Effects of endogenous and some exogenous factors on the activity of the juvenile banana prawn Penaeus merguiensis

In conditions of alternating light and dark, juvenile Penaeus merguiensis de Man are more active during the dark phase. The rhythm persists in continuous dim red light, but not in continuous bright white light. The period of circadian rhythm shown in continuous dim red light varies between individuals from 22.75 to 26.0 h, with a mean of 23.8 h. The response of prawns to an artificially produced tidal situation is mediated by the presence or absence of water flow. No endogenous component of this tidal rhythm was demonstrated. There is an irregular short-term rhythm (period 2 to 3 h). It is suggested that this allows starved prawns to conserve energy.

A description of the development of primary and secondart sexual characters in the banana prawn, Penaeus merguiensis de Man (Crustacea: Decapoda: Penaeinae)

A description is given of the metamorphosis and functional aspects of male and female genitalia in Penaeus merguiensis de Man, and criteria for the designation of adult genitalia are presented. Male and female primary sexual development is described and the effect of parasitism by the bopyrid crustacean Epipenaeon sp, on primary and secondary sexual development is outlined. Some aspects of mating and spawning are discussed.