Spatio-temporal distribution and habitat preferences of cetaceans in Algoa Bay, South Africa

Increasingly, baseline knowledge of habitat preferences and movement patterns of marine species is required to inform anthropogenic developments. The aim of this study was to determine baseline spatio-temporal distribution and habitat preference of cetaceans in the coastal waters of Algoa Bay. Areas of potential conflict with anthropogenic activities were also assessed. Monthly sea-based surveys were conducted between June 2008 and May 2011. A total of 500 cetacean sightings comprising six species were recorded in 106 surveys. Tursiops aduncus (Indo-Pacific bottlenose dolphin), Sousa plumbea (Indian Ocean humpback dolphin), Delphinus capensis (long-beaked common dolphin) and Balaenoptera brydei (Bryde's whale) were observed year-round, while Eubalaena australis (southern right whale) and Megaptera novaeangliae (humpback whale) were recorded from May to December. A large portion of sightings were associated with a Marine Protected Area and shipping zones. Eubalaena australis, T. aduncus and S. plumbea were found inshore (water depths < 12 m), while the other species were associated with deeper waters. Tursiops aduncus were most commonly seen (233 sightings). Megaptera novaeangliae were sighted often in austral winter, with 113 sightings. Only nine D. capensis sightings were recorded. Spatial distributions of species were corrected for search effort to identify habitat preferences. A number of key observations were made, including opportunistic foraging in M. novaeangliae, and the expansion of nursery grounds for E. australis, to include Algoa Bay. Four preferred habitat areas are proposed, providing important information for conservation and management of cetaceans in Algoa Bay. The spatial approach can be used to inform future relevant management decisions elsewhere.

Cetaceans observed in Suriname and adjacent waters

Very little information exists about the cetaceans in the Guianas: Suriname and its neighboring countries Guyana and French Guiana. During a dedicated cetacean survey carried out from a geophysical seismic survey vessel in the offshore waters of Suriname (May-September 2012), the occurrence of 13 cetacean species was documented and of those, 11 were newly documented for this area. The species observed by the author included sperm whale (Physeter macrocephalus), Bryde’s whale (Balaenoptera edeni), false killer whale (Pseudorca crassidens), melon-headed whale (Peponocephala electra), roughtoothed dolphin (Steno bredanensis), long-beaked common dolphin (Delphinus capensis), Fraser’s dolphin (Lagenodelphis hosei), pantropical spotted dolphin (Stenella attenuata) and spinner dolphin (Stenella longirostris). During transit to the survey area (Trinidad to Suriname) incidental sightings were recorded which included common bottlenose dolphin (Tursiops truncatus) off Trinidad, Stenella sp. off Guyana and Guiana dolphin (Sotalia guianensis) at the entrance of the Suriname River. Opportunistic records originating from the periods December 2008-March 2009 and August-October 2012 were forwarded to the author. These records included common bottlenose dolphin, Atlantic spotted dolphin (Stenella frontalis) and short-finned pilot whale (Globicephala macrorhynchus). There is a growing need to identify critical areas for marine biodiversity conservation, both locally and regionally. This paper describes the general occurrence of the cetacean community encountered in Suriname waters in summer. The study revealed that the offshore cetacean community in Suriname is best described as primarily a tropical community, dominated by odontocetes (dolphins and sperm whales). Although the species diversity was relatively high, the overall cetacean relative abundance index (number of animals per 100km effort) was low, which is consistent for tropical equatorial offshore waters. Apart from the sperm whale and the Guiana dolphin, all the other species recorded represent new species records for Suriname. It is recommended that more continuous monitoring in different seasons be carried out in order to gain a better understanding of the occurrence, distribution and status of the different cetacean species within the region.

174 RECOVERY OF LONG-BEAKED COMMON DOLPHIN OOCYTES FROM KOREAN WATERS

The aims of this study were to collect oocytes from ovaries of Delphinus capensis (long-beaked common dolphin) and to examine the morphological characteristics of their reproductive organ. Female genital organs were collected from 2 incidentally caught Delphinus capensis (ID-96: estimated 5–6 years, and ID-97: estimated 7–8 years). Collected ovaries were transported to the laboratory over 3.5 h in 0.9% saline at 39°C. To perform assisted reproductive techniques in wild animals, it is important to maximize the number of oocyte recovered per ovary. In this study, Delphinus capensis oocytes were collected by 2 methods: (1) aspiration of visible follicles (2 to 3 mm in diameter) and (2) remnant dissection, in which the ovary is finely dissected. The collected cumulus–oocyte complexes (COC) were separated by ovary of origin and collection method. Oocytes were subjected to in vitro maturation (IVM). Immature oocytes were placed into IVM medium [TCM-199 supplemented with 10% (vol/vol) fetal bovine serum, 0.5 IU mL–1 LH, and 0.5 IU mL–1 porcine FSH] in the 4-well dish for 120 h at 37°C in 5% CO2 in a humidified atmosphere. The uterus type was observed to be a uterus bicornis. Morphology of ovary was similar to the bovine ovary among land animals. In total, 114 oocytes were obtained. From the ovary of ID-97, the number of oocytes recovered by aspiration and ovary dissection were 15 and 57, respectively. However, only 42 oocytes were recovered by ovary dissection from the ovary of ID-96. The number of oocytes recovered per ovary by dissection (49.5 ± 7.5) was higher than that by the aspiration (7.5 ± 7.5) method, but not significantly different (P = 0.06). For accurate statistical analysis, additional trials will be performed. Most oocytes had either no cumulus cells or had only 1 to 2 layers attached to the zona pellucida enclosing a homogeneous cytoplasm. After IVM, all oocytes were at the metaphase I stage, with even fewer attached cumulus cells than at recovery. To summarise, we describe the gross morphology of the female reproductive tract of the long-beaked common dolphin and determined that dissection of the ovary is required for maximal recovery of oocytes. This work was supported, in part, by a grant from the Next-Generation Bio Green 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.