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Concern for New Jerseys' dolphins
(See update at bottom of item)
Despite reassurances from a panel of wildlife experts, concerns are growing for a group of dolphins that first appeared in the Shrewsbury/Navesink River (New Jersey) back in June 2008. Water temperature in the two rivers is now 35 degrees, a massive drop from the 60+ degrees it was when the dolphins first appeared.
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The National Oceanic and Atmospheric Administration (NOAA) recently held a public/press teleconference to reassure those concerned that plunging temperatures would not cause the remaining 12 bottlenose dolphins to freeze to death in the rivers. They also gave a short presentation on the current situation, including updates on dolphin behaviour, condition and numbers; the ongoing collection of data on noise in the river; and necropsy results on two dolphins that died earlier this year. However concerns still prevail as four dolphins that lingered in the very same area in 1993 did die due to the fact that ice eventually closed in on them causing the animals to drown. |
NOAA insists however there are more risks involved by moving the animals than to keep them where they are, however some conservationists disagree and want them either removed or coaxed out of the river back out to sea. Whilst it is unclear why the dolphins strayed into the area, moving the animals can cause many potential problems, including elevating their possibly already high stress levels.
A spokesperson for the Marine Connection comments “It’s always difficult to say why dolphins stray into rivers, one reason however could be due to the abundance of food stock in the area. So far they appear to be in good body condition and although there are young calves amongst the group, they would easily have the ability to swim to deeper water.”
Lone dolphins and smaller groups have occasionally been sighted in the Shrewsbury/Navesink River system over the years but this is by far the largest group that has been recorded so far. It could be an example of the northern coastal bottlenose dolphin population expanding its range in response to environmental conditions such as changing average water temperatures and prey distribution. Coastal bottlenose dolphins quite commonly occur in rivers and can tolerate a wide range of environmental conditions, for example salinity and temperature fluctuations, so long as they are in good body condition, have sufficient food source and are not otherwise ill or injured.
The Marine Connection will of course continue to update news as things develop with the ongoing situation for these dolphins.
Update 29.12.08
A female dolphin that was found dead on Christmas Day and related to this particular pod, was pregnant. A necropsy was carried out and it was also found that the female had not eaten recently as no fresh food was found in her stomach.
Update 08.01.09
We have recently heard that only five of the original pod remains, and more are likely to die. At least six dolphins are unaccounted for since December and some of the remaining animals appear to have lost weight in recent weeks. There are no plans to remove the dolphins from the area.
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