Size and diel differences in activity patterns ofMetapenaeus ensis, penaeus latisulcatusandP. merguiensis

Abstract

The nursery function of mangroves as shelter has been postulated to explain the positive correlation between shrimp catches and mangrove area. This study was undertaken to document shelter use and other activities in mangrove-associated penaeids and to determine diel and size differences relating to these activities. Juvenile Metapenaeus ensis, Penaeus latisulcatus and P. merguiensis collected from mangrove areas in Guimaras, central Philippines and stocked individually in glass tanks (= replicates) provided with artificial shelters and sand substrate were observed every hour for 25 h. Size classes tested were very small (1-5.9 mm carapace length); small (6-10.9mm CL); medium (11-15.9mm CL); large (16-20.9mm CL); and very large (21-25.9 mm CL). Due to limited juvenile supply, only 3 sizes were tested for each species: P. merguiensis (very small to medium), M. ensis (small to large) and P. latisulcatus (medium to very large) with 5 replicate animals (one per tank) per size. Juvenile M. ensis and P. latisulcatus showed a strong diel periodicity of daytime burial and nocturnal activity. In contrast, P. merguiensis showed active swimming and feeding throughout the day and night. Very small to small P. merguiensis were observed on the shelters, but burying was exhibited only by a few medium-sized juveniles. This shelter use is consistent with observations of small P. merguiensis entering the mangrove forest (where roots, twigs, etc. contribute to structural complexity) on the flood tide and concentrating in the shallow, turbid waters of adjoining creeks during ebb tide and slack water.

Activity pattern of the marine shrimp Litopenaeus vannamei (Boone 1931) in laboratory as a function of different feeding frequencies

“…Primavera & Lebata (2000), based on 25 hourly laboratory observations, also found higher activity levels between Metapenaeus ensis (De Haan 1844), Penaeus latisulcatus (Kishinouye 1896) and Fenneropenaeus merguiensis (De Man 1888) juveniles during the dark phase. M. ensis and P. latisulcatus juveniles displayed a pattern of burrowing themselves into the substrate during the day and emerging at night.…”

“…Part of the knowledge of shrimp activities has been acquired from studies quantifying activity versus inactivity of the animal through the use of photocells, without discriminating between the different activities performed by these animals (Rodriguez & Naylor 1972; Hindley 1975; Reynolds & Casterlin 1979; Vance 1992; Guerao & Ribera 1996). Ethological studies applied to shrimp farming are rare (Primavera & Lebata 1995, 2000). With L. vannamei specifically, some studies have been developed that show their daily activity pattern differentiating each one (Pontes & Arruda 2005a, b; Pontes, Arruda, Menezes & Lima 2006).…”

“…Primavera & Lebata (2000), based on 25 hourly laboratory observations, also found higher activity levels between Metapenaeus ensis (De Haan 1844), Penaeus latisulcatus (Kishinouye1896) and Fennerope-Feed o¡er and activities pattern in L. vannamei P P de Lima et al Aquaculture Research, 2009, 41, 53^60 r 2009 The Authors…”

Nursery ground value of an endangered wetland to juvenile shrimps

“…Secondly, although mangrove carbon has been shown to be the most important contributor to nutrition of F. merguiensis in other studies of Malaysian mangrove systems (Chong et al 2001), in the Gulf of Carpentaria Australia its contribution is equivocal and localised to areas immediately adjacent to mangrove forests (Loneragan et al 1997). The results from the Annandale Wetland suggest that aspects of mangrove systems other than the supply of mangrove carbon (e.g., the provision of shelter (Primavera and Lebata 2000)) may determine the distribution of juvenile F. merguiensis.…”