مجله بین المللی زیست شناسی آبزیان
سال:1396 | دوره:5 | شماره:4 |تعداد مقالات:8

The quality of the invader brine shrimp, Artemia franciscana, colonized in Covelong saltworks, Kelambakkam (South India) was evaluated based on biometrics, hatching characteristics andnutritional composition of cyst and freshly hatched nauplii. Hydrated cysts measured 238.31±10.42mm in diameter, while the freshly hatched nauplii measured about 429.00±12.19 mm in length. Ahatching of 76.80±5.68% was obtained with hydrated cysts. Time required to obtain 90% hatchingwas 22.31 hrs for this strain. The hatching synchronization time was of 4.41 hrs. The proximatecomposition of the decapsulated cysts and newly hatched nauplii showed high level of protein, energycontent and low ash content. Fatty acids analysis of the freshly hatched nauplii indicated low levelof EPA and absence (or undetectable) of DHA.

The size distribution, allometric growth pattern, stomach analysis and sex ratio of the WestAfrican fiddler Crab, Uca tangeri in a mangrove wetland were investigated. The carapace lengthranged from 1.11-3.7 cm and the weight 7.7-25.5 g. The crab exhibited negative allometric growth(b<3). No linear relationship was found between length and weight of U. tangeri as correlationcoefficient (r) was 0.2464 for combined sexes. The condition factor ranged between 4.7 and 12.1, varying in relation to size and sex. The crabs fed mainly on detritus, diatoms, and algae with higherpreference for plant materials. The males were significantly more numerous than females with theratio 1: 0.6. Uca tangeri is an ecologically important species in our marsh. Therefore, mangroveecosystem should be effectively monitored for the conservation of this species.

The annelid ‘fireworm’ Hermodice carunculata is widely recorded in clear shallow watersof the tropical Atlantic Ocean and adjacent seas, where it inhabits hard substrata. It is an omnivoreand opportunistic scavenger, feeding strategies considered central to the maintenance of its broadgeographic distribution. Hermodice carunculata also preys on various cnidarians, and starfish. Thisstudy represents the first report of active predation by H. carunculata on living specimen of theholothurian Isostichopus badionotus, from the southwestern Atlantic, Brazilian coast. The fact thatparts of living holothurians were consumed, excluded the possibility of scavenging behavior. Suchpredatory behavior is described here for the first time, corroborates that H. carunculata feeds onEchinoderms other than starfish. However, we cannot presently answer the question whetherH. carunculata actively preys on healthy holothurians or opportunistically feeds on injured seacucumbers.