In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.
|EPBC Act Listing Status||Cetacean|
|Adopted/Made Recovery Plans|
|Policy Statements and Guidelines||
Marine bioregional plan for the North-west Marine Region (Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC), 2012y) [Admin Guideline].
Industry Guidelines on the Interaction between offshore seismic exploration and whales (Department of the Environment and Water Resources (DEW), 2007h) [Admin Guideline].
Australian National Guidelines for Whale and Dolphin Watching (Department of the Environment and Heritage, 2005e) [Information Sheet].
|Non-statutory Listing Status||
|Scientific name||Stenella coeruleoalba |
This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.
Scientific name: Stennella coeruleoalba
Common name: Striped Dolphin, Euphrosyne Dolphin
Other names: Blue-white Dolphin
The Striped Dolphin was first named formally by F. Meyen in 1833 as Delphinus coeruleoalbus, from a specimen collected off the River Plate in South America. Despite its widespread occurrence in warm-temperate and tropical waters of the world, no subspecies have been described. Striped Dolphins show only moderate geographical variation in skeletal morphometrics and little in pigmentation (Culik 2003j). There is no information on the taxonomic status of the few Australian specimens.
Striped Dolphins are robust dolphins with diagnostic patterns of blue and white stripes and blazes along the lateral and dorsal sides (hence the species name "coeruleoalba", meaning blue and white). The dorsal cape is muted blue or blueish-grey, most often with a white or light grey spinal blaze. The belly is lighter than the sides. The beak is long and well defined, and the dorsal fin is falcate (sickle-shaped) (Reeves et al. 2003).
The maximum recorded length of male and female Striped Dolphins is 2.6 m and 2.5 m respectively. However measurements made in the Mediterranean Sea suggest lengths asymptote at 2.00 m and 1.94 m in males and females respectively (Calzada et al. 1997). Male Striped Dolphins reach physical maturity at 1520 years of age, while females mature earlier, at 1318 years of age (Calzada et al. 1997). In the Mediterranean, sexual maturity is reached at 1112 years in both sexes (Reeves et al. 2003), but has declined from 9.7 years to 7.2 years in females off Japan thought to be in response to decrease in numbers caused by the fishery for this species (Perrin et al. 1994). Individuals may live for about 58 years.
This species is gregarious, usually in schools of a few hundred, though groups of up to several thousand individuals occur. Schools may be made up of subadults, adults or mixed ages. Subadult schools may move closer to the coast than adult or mixed schools. Striped Dolphins are active and conspicuous and may ride bow waves.
Strandings of Striped Dolphins are infrequent in Australian waters. Four or five records are known from Western Australia, including the most southerly, from Augusta in south-western Western Australia, which is probably related to the southward flow of the warm Leeuwin Current in this region. There are two records from NSW, and two from southern Queensland (Ross 2006).
The current extent of occurrence of Striped Dolphins is estimated to be greater than 20 000 km² (based on the Australian Exclusive Economic Zone (EEZ) (200 nm, north of 34º S and deeper than 200 m) (Peddemors & Harcourt 2006, pers. comm.). No past declines in extent of occurrence are known, and no future changes are anticipated. However, increased ocean temperatures predicted by climate change scenarios could potentially increase the extent of occurrence with warmer water extending beyond 34° S.
The area of occupancy of Striped Dolphins cannot be calculated due to the sparsity of sighting records for a large proportion of the range. However, it is likely to be greater than 2000 km² (Peddemors & Harcourt 2006, pers. comm.). No past declines in extent of occurrence are known, and no future changes are anticipated. However, future expansion of pelagic gillnet fisheries may result in increased incidental catches, potentially depleting local waters and leading to a decrease in area of occupancy.
It is anticipated that the Striped Dolphin occurs in one population as deep water is not a barrier to movement in this species.
No distribution fragmentation is anticipated for populations of Striped Dolphins in Australian waters.
The Striped Dolphin is a temperate to tropical species. It inhabits deep oceanic waters, ranging north in the Atlantic to Newfoundland and southern Greenland and Iceland, in the Pacific to the Sea of Japan, Hokkaido (about 40° N) and across to British Columbia. Their southern limit is Buenos Aries, Argentina to Cape Province, Western Australia and New Zealand. In the southern Pacific they are not found off West Africa. A skull from Robinson Crusoe Island (33°42'S, 80°45'W) constitutes the most southern distribution limit in the offshore temperate southeast Pacific (Cardenez et al. 1997), though otherwise Striped Dolphins are not sighted south of latitude 21° S (Van Waerebeek et al. 1998). They are also common in the Mediterranean Sea (Leatherwood & Reeves 1983).
Population estimates for Striped Dolphins are available for only a subset of its range:
- Off Japan - Population estimates of Striped Dolphin numbers for Japan suggest that 570 000 individuals may occur in the waters from 25°41° N and 135°180° E during August and September (Miyashita 1993).
- Eastern tropical Pacific - From 635 000 to 2 251 300 individuals are thought to occur in the eastern tropical Pacific (Perrin et al. 1994; Wade & Gerrodette 1993).
- Western Mediterranean Sea - The population in the Western Mediterranean Sea was estimated at 117 880 animals in 1991, during the period that the 19901992 morbillivirus epizootic developed in the region (Forcada et al. 1994).
- Californian waters - Barlow (1995) estimated abundance at 12 300 for California waters from the coast out to 555 km.
- Australia - There are no estimates for the number of Striped Dolphins occurring off Australia (Bannister et al. 1996).
A Japanese drive fishery for dolphins has existed on the East China Sea coast since the 15th century. In the 19th century, the fishery operated on temperate and tropical species in at least six regions of the Sea of Japan, East China Sea and Pacific (Kishiro & Kasuya 1993). In recent years the fishery has operated (under governmental license from 1982) from two villages on the Pacific coast: Taiji on the Kii Peninsula and Futo on the Izu coast. On the Izu coast, catches mainly consist of Striped Dolphins with some additional Bottlenose Dolphins and southern form Short-finned Pilot Whales. Over 10 000 Striped Dolphins were taken by this fishery before 1960, but the catch declined to below 1000 by the early 1980s despite effort remaining unchanged. Taiji began a post-war drive fishery in 1969 targeting Striped Dolphins and southern form Short-finned Pilot Whales. The Taiji fishery expanded the list of target species to include Bottlenose Dolphins, Spotted Dolphins, False Killer Whales and Risso's Dolphins during the period that Striped Dolphin catch declined from between 3000 and 11 000 in the early 1980s to less than 1000 in more recent years. Kishiro and Kasuya (1993) conclude that the availability of Striped Dolphins to the drive fisheries on the Pacific coast has declined over the past 30 years. In addition to the Pacific fisheries, approximately 3500 Striped Dolphins are taken by both direct and indirect fisheries off the coast of Sri Lanka annually (Alling 1988).
There are no estimates of Striped Dolphin population size, either globally or for Australia, so the proportion of the global population in Australian waters is unknown. Striped Dolphins are believed to be common throughout their range. However, it is thought that one third of schools avoid boats (Wursig et al. 1998), making abundance difficult and potentially underestimating population numbers.
It is likely that Striped Dolphins move between Australia and other countries due to the lack of any deep water barriers.
The Striped Dolphin is not well surveyed in Australian waters, and its distribution is primarily assumed from beach-cast animals. However, this method is believed to result in reliable distributional information for the species.
Although no population size is known, the Striped Dolphins are not considered rare. From 635 000 to 2 251 300 individuals occur in the Eastern Tropical Pacific (Perrin et al. 1994). The species is therefore potentially abundant in Australian waters, and certainly likely to exceed 10 000 mature individuals (Peddemors & Harcourt 2006, pers. comm.).
Lack of abundance and distribution data do not allow definitive assessment of the potential for subpopulations of Striped Dolphins, but elsewhere in the range the distribution appears contiguous. There is clear genetic differentiation between the Mediterranean and Atlantic populations (Garcia-Martinez et al. 1999), and some evidence of more than one stock off Japan (Kasuya 1999). There may therefore be more than one stock in Australian waters.
No population trends can be calculated due to a paucity of survey data for Striped Dolphins. However, the population can be assumed to have been nominally reduced due to human-induced mortalities. Ongoing incidental captures and directed takes are the most likely cause of potential future population decline, although no quantitative data are available.
As the Striped Dolphin is not known to migrate, its population is not anticipated to undergo any extreme fluctuations.
All cetaceans are protected within The Australian Whale Sanctuary under the EPBC Act 1999. The Sanctuary includes all Commonwealth waters from the three nautical mile state waters limit out to the boundary of the EEZ (200 nm and further in some places). The Striped Dolphin is also subject to International Whaling Commission (IWC) regulations and protected within the Indian Ocean Sanctuary and Southern Ocean Sanctuary.
The Striped Dolphin inhabits pelagic and oceanic waters. All sightings have been made in waters where the sea surface temperature exceeds 25 °C.
Striped Dolphins may travel in large groups of several hundreds and even thousands, and are most frequently found in deep waters (deeper than 1000 m), preferring areas with large seasonal changes in surface temperature and thermocline depth and with seasonal upwelling (Au & Perryman 1985).
Common and Striped Dolphins tend to frequent the same areas, and may be seen less frequently with Spotted and Spinner Dolphins, Pilot Whales and Risso's Dolphins (Au & Perryman 1985; Frantzis & Herzing 2002).
The biological information presented in this profile is primarily based on limited and non-Australian information (Miyazaki & Perrin 1994; Perrin & Reilly 1984). The age at sexual maturity is 1112 years in both sexes in the Mediterranean (with average length at sexual maturity of 187 cm for females) (Aguilar 2000). The age at sexual maturity declined from 9.7 years (1956 cohort) to 7.2 years (1970 cohort) in females off Japan, thought to be in response to decrease in numbers caused by the fishery for this species (Kasuya 1985). This was accompanied by a decline of the minimum age at physical maturity and a shortening of the mean reproductive cycle from four years (1955) to less than three years (1977) (Kasuya 1985). In the Mediterranean Sea, age and length at physical maturity occurs at 1520 years of age in males, and 1318 years of age in females (Calzada et al. 1997). The maximum age is about 58 years (Calzada et al. 1997).
The calving interval within the Mediterranean population is four years, with an annual pregnancy rate of 25%, and an ovulation rate of 0.401 (Calzada et al. 1996). The mating season unknown, and the calving season is prolonged. Gestation lasts about 12 months. Calves are born between 0.8 and 1.0 m in length, and wean at 1536 months and 1.7 m in length. It is suspected that the calving interval is two to three years. No calving areas are known in Australian waters (Bannister et al. 1996; Perrin & Reilly 1984; Perrin et al. 1994).
Prey is small (<300 mm length), and includes mesopelagic fish, shrimp and squid. Cephalopods dominate in the Mediterranean, while myctophids dominate off Japan and South Africa (Culik 2003j).
Striped Dolphins are gregarious, and are usually seen in schools of a few hundred, though groups of up to several thousand individuals occur. Striped Dolphins may feed at depths of about 200 m or may take prey species that normally live at such depths when they come to surface at night (Baker 1990; Perrin et al. 1994). Striped Dolphins do not co-occur with tuna as commonly as Spotted and Spinner Dolphins do, and so are less vulnerable to being entangled and caught in tuna purse seine nets (Au & Perryman 1985).
Striped Dolphins are most likely to be confused with Common Dolphins (Delphinus delphis) but are easily distinguished by their robust body and distinct colouration. The tall falcate dorsal fin and distinctive colour pattern should enable rapid identification in mixed-species groups.
Cetacean surveys are constrained by several important factors including weather (e.g. sea state and light conditions), area to be covered, aim of the survey (abundance estimate versus ecological studies), the activities of the animals themselves (e.g. travelling, resting, surface versus deep feeding), and the type of craft used for the survey.
Surveys for pelagic dolphins have primarily been boat-based transects, although some aerial surveys have been conducted in the Eastern Tropical Pacific. Almost no dedicated cetacean surveys are conducted in Australian northern waters, but surveys associated with petro-chemical exploration may be used as platforms of opportunity. The minimum recommended requirement for cetacean surveys is to obtain basic biological information from incidentally-caught animals from fishing vessels. One biologist on fishing vessels for one year is recommended (Peddemors 2006, pers. comm.).
The current and future potential threats to the Striped Dolphin include:
- Direct catches in waters to the north of Australia, including Indonesia, Solomon Islands, Japan and Papua New Guinea.
- Illegal catches within the Australian EEZ by fishers from nearby countries.
- Possible illegal and incidental catches by fishers in northern Australian waters.
- Incidental capture in pelagic drift-net and gill-net fisheries off Sri Lanka (Ailing 1988; Ross 2006).
- Entanglement in drift-nets set outside Australian Territorial Waters and in lost or discarded netting.
- Pollution (including increasing amounts of plastic debris at sea, oil spills and dumping of industrial wastes into waterways and the sea) leading to bio-accumulation of toxic substances in body tissues (Bannister et al. 1996).
The low reproductive rate of Striped Dolphins (one offspring every three to four years) means that population recovery is a slow process.
Bannister and colleagues (1996) and Ross (2006) recommended the following measures be taken to better understand the threats to the Striped Dolphin:
- Determine distribution and monitor abundance in Australian waters to assess possible impact of threats, particularly the effect of direct and indirect fishing activities. This may be done via a sighting program to monitor numbers, particularly in northern waters.
- Obtain information on diet to determine trophic level and assess possible impact of fishing industry on food resources.
- Determine taxonomic and population structure relationships within and outside Indo-Pacific region to assess likely impact of threats on possible individual populations.
- Obtain basic biological information (including diet and pollutant levels) from incidentally-caught and stranded specimens, especially from Arafura and Timor seas. This should include ensuring specimens are made available to appropriate scientific museums.
Disentanglement workshops have been initiated, and may be particularly relevant for offshore fishers.
Marine bioregional plans have been developed for four of Australia's marine regions - South-west, North-west, North and Temperate East. Marine Bioregional Plans will help improve the way decisions are made under the EPBC Act, particularly in relation to the protection of marine biodiversity and the sustainable use of our oceans and their resources by our marine-based industries. Marine Bioregional Plans improve our understanding of Australia's oceans by presenting a consolidated picture of the biophysical characteristics and diversity of marine life. They describe the marine environment and conservation values of each marine region, set out broad biodiversity objectives, identify regional priorities and outline strategies and actions to address these priorities. Click here for more information about marine bioregional plans.
The Striped Dolphin has been identified as a conservation value in the North-west (DSEWPaC 2012y) Marine Region. The "species group report card - cetaceans" for the North-west (DSEWPaC 2012y) Marine Region provides additional information.
The Action Plan for Australian Cetaceans (Bannister et al. 1996) and the Review of the Conservation Status of Australia's Smaller Whales and Dolphins (Ross 2006) provide brief biological overviews and management recommendations of this species. In addition, Industry Guidelines on the Interaction between offshore seismic exploration and whales (DEW 2007h) and Australian National Guidelines for Whale and Dolphin Watching (2005c) have been published.
No threats data available.
Alling, A. (1988). Preliminary Report of the Incidental Entrapment of Odontocetes by Sri Lanka's Coastal Drift Net Fishery. Journal of the Bombay Natural History Society. 85(3):538-550.
Au, D.W.K. & W.L. Perryman (1985). Dolphin Habitats in the Eastern Tropical Pacific. Fishery Bulletin. 83(4):623-644.
Baker, A. (1990). Whales and Dolphins of Australia and New Zealand: An Identification Guide. Page(s) 133 pp. Wellington, New Zealand: Victoria University Press.
Bannister, J.L., C.M. Kemper & R.M. Warneke (1996). The Action Plan for Australian Cetaceans. [Online]. Canberra: Australian Nature Conservation Agency. Available from: http://www.environment.gov.au/resource/action-plan-australian-cetaceans.
Barlow, J. (1995). The abundance of cetaceans in California waters: Part I. Ship surveys in summer and fall of 1991. US National Marine Fisheries Service Fishery Bulletin. 93:1-14.
Calzada N, A.Aguilar, T.B. Sorensen & C. Lockyer (1996). Reproductive biology of female striped dolphin (Stenella coeruleoalba) from the western Mediterranean. Journal of Zoology, London. 240(3):581-591.
Calzada, N., A. Aguilar, C. Lockyer & E. Grau (1997). Patterns of growth and physical maturity in the western Mediterranean striped dolphin (Stenella coeruleoalba) (Cetacea: Odontoceti). Canadian Journal of Zoology. 75:632-637.
Culik, B. (2003j). Stenella coeruleoalba (Meyen, 1833). Review on Small Cetaceans: Distribution, Behaviour, Migration and Threats. [Online]. Available from: http://www.cms.int/reports/small_cetaceans/data/S_ceoruleoalba/s_coeruleoalba.htm. [Accessed: 30-Oct-2007].
Department of the Environment and Heritage (2005e). Australian National Guidelines for Whale and Dolphin Watching. [Online]. Available from: http://www.environment.gov.au/resource/australian-national-guidelines-whale-and-dolphin-watching-2005.
Department of the Environment and Water Resources (DEW) (2007h). Industry Guidelines on the Interaction between offshore seismic exploration and whales. [Online]. Available from: http://www.environment.gov.au/epbc/publications/seismic.html.
Forcada, J., A. Aguilar, P.S. Hammond, X. Pastor & R. Aguilar (1994). Distribution and numbers of striped dolphins in the western Mediterranean Sea after the 1990 epizootic outbreak. Marine Mammal Science. 10:137-150.
Frantzis, A. & D.L. Herzing (2002). Mixed-species associations of striped dolphins (Stenella coeruleoalba), Common Dolphins (Delphinus delphis), and Risso's dolphins (Grampus griseus) in the Gulf of Corinth (Greece, Mediterranean Sea). Aquatic Mammals. 28:188-197.
Garcia-Martinez J, Moya A., J.A. Raga & A. Latorre (1999). Genetic differentiation in the striped dolphin Stenella coeruleoalba from European waters according to mitochondrial DNA (mtDNA) restriction analysis. Molecular Ecology. 8(6):1069-1073.
Kasuya, T. (1985). Effect of Exploitation of Reproductive Parameters of the Spotted and Striped Dolphins Off the Pacific Coast of Japan. Scientific Reports of the Whales Research Institute Tokyo. (36):107-138.
Kasuya, T. (1999). Review of the biology and exploitation of striped dolphins in Japan. Journal of Cetacean Research & Management. 1(1):81-100.
Kishiro T. & T. Kasuya (1993). Review of Japanese dolphin drive fisheries and their status. Report of the International Whaling Commission. 43:439-452.
Miyashita, T. (1993). Abundance of dolphin stocks in the western North Pacific taken by the Japanese drive fishery. Report of the International Whaling Commission. 43:417-437.
Peddemors, V.M. (2006). Personal Communications. Sydney: Graduate School of the Environment, Macquarie University.
Peddemors, V.M. & R. Harcourt (2006). Personal Communication. Sydney: Graduate School of the Environment, Macquarie University.
Perrin, W.F. & S.B. Reilly (1984). Reproductive parameters of dolphins and small whales of the family Delphinidae. Reports of the International Whaling Commission (Special Issue 6). Page(s) 97-133.
Perrin, W.F., S. Leatherwood & A. Collet (1994). Fraser's dolphin - Lagenodelphis hosei (Fraser, 1956).The first book of dolphins. Ridgway S.H. & Harrison S.R., eds. Handbook of Marine Mammals. 5:225 - 240. Academic Press, London.
Reeves, R.R., B.D. Smith, E.A. Crespo & G. Notarbartolo di Sciara (2003). Dolphins, Whales and Porpoises: 2002-2010 Conservation Action Plan for the World's Cetaceans. Page(s) 139. IUCN/SSC Cetacean Specialist Group.
Ross, G.J.B. (2006). Review of the Conservation Status of Australia's Smaller Whales and Dolphins. Page(s) 124. [Online]. Report to the Australian Department of the Environment and Heritage, Canberra. Available from: http://www.environment.gov.au/resource/review-conservation-status-australias-smaller-whales-and-dolphins.
Van Waerebeek, K., F. Felix, B. Haase, D.M. Palacios, D.M. Mora Pinto & M. Munoz Hincapie (1998). Inshore records of the striped dolphin, Stenella coeruleoalba, from the Pacific coast of South America. Report of the International Whaling Commission. 0(48):525-532.
Wade P. & T.Gerrodette (1993). Estimates of cetacean abundance and distribution in the eastern tropical Pacific. Report of the International Whaling Commission. 43:477-493.
Wursig, B., S.K. Lynn, T.A. Jefferson & K.D. Mullin (1998). Behavior of cetaceans in the northern Gulf of Mexico relative to survey ships and aircraft. Aquatic Mammals. 24:41-50.
This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.
Citation: Department of the Environment (2014). Stenella coeruleoalba in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Thu, 24 Jul 2014 22:02:32 +1000.