Observation on Marine Copepod - Appendicularian Naturally Changing Concentrations Along Southwest Coast of India

Abstract

Patterns of copepod -appendicularian distribution were studied along the Mangalore coastal waters (12°50'49" N; 74°48'50" E) of the Arabian Sea to understand the food and feeding relationship existing among these groups. Sampling was conducted during premonsoon, monsoon and post-monsoon extending from January 2009 to December 2010. The copepod and appendicularian community was sampled with a 60 µm net to include the smallest species and their developmental stages. Copepod biomass, especially calanoids, was substantially high throughout the study. Seasonal mean results showed that the small-sized copepods (calanoids, harpacticoida and cyclopoids) dominated in terms of biomass and production. Calanoids found in abundance included Acartia, Centropages, Calanus, Eucalanus and Labidocera. Cyclopoid and Harpacticoid copepods genera dominated included Oithona, Oncaea and Microsetella, Macrosetella. Appendicularian species diversity was represented by Oikopleura fusiformis, O. dioica and its juveniles represented as Oikopleura sp. Total chlorophyll (chlorophyll a) ranging between 10 and 20 mg m -3 indicated the eutrophic state as well as productivity prevailing during the study period. Principal component analysis (PCA) indicated the routine and opportunistic seasonal grazers and establishes a phytoplankton -appendicularia -copepod -fish food chain relationship along Mangalore coast.

A Principal Component Analysis (PCA) Approach to Seasonal and Zooplankton Diversity Relationships in Fishing Grounds of Mannar Gulf, India

“…Similar inference could be noted from earlier studies in Gulf of Mannar and in Gulf of Maine (Pershing et al, 2005). The results of the present study thus agreed with findings in other regions and explained that copepods constituted the major taxa in Catalan Sea , in Arabian Sea (Madhupratap et al, 2001;Jose et al, 2012), and in Mondego estuary (Marques et al, 2007).…”

“…Two different principal components (PC) were segregated in all the seasons homogeneously. The component matrix which is exceeding 0.6 could be taken for interpretation in the present study (Udayakumar et al, 2009;Jose et al, 2012). , Dotilla fenestrate and Nauplius of balanus were showed with positive significant correlation, which indicated their preference for sharing the same feeding habitat devoid of antagonism as suggested by Jose et al (2012).…”

“…Acartia spinicauda, Copepodite labidoceropavo, Nannocalanus minor, Pseudodiaptomus sp., Euchaeta marina, Oithona brevicornis, Corycaeus danae, Tintinnopsis cylindrical, Crab zoea, Labidocera acuta, Leucosiidae zoea, Mysis larvae, Cypris of balanus were negatively correlated at significant level due to the grazing pressure from the positive significant zooplankton groups, suppressing the species of negatively significant zooplankon species by the way of dragging away from their feeding ground (Jose et al, 2012).…”

“…The component matrix which is exceeding 0.6 could be taken for interpretation in the present study (Udayakumar et al, 2009;Jose et al, 2012). , Dotilla fenestrate and Nauplius of balanus were showed with positive significant correlation, which indicated their preference for sharing the same feeding habitat devoid of antagonism as suggested by Jose et al (2012). However, the positive loadings in the PC1, most of the copepods species were herbivores, except that of Oithona rigida and O. spinirostris as similarly reported by Madupradap et al (2003).…”

“…and Globigerina spp. It was thus clearly noticed that, the significant positive loading species of copepods, which were also dominant exerted grazing pressure, which in turn depressed the remaining copepods by the way of squeezing them away from their feeding grounds (Jose et al, 2012). However, during the post monsoon season, most of the copepods remain there and only a few opportunistic species invade the fishing grounds with respect to the seasonal current pattern, as well as grazing pressure.…”