The Department of Environment and Natural Resources (DENR) has received a number of reports of dead fishes washing up on shorelines around the island. A department spokesperson noted, “We would like to thank those members of the public who have taken the time to contact us. We record all reports of this nature, regardless of how minor they may appear, as it helps us to track the timing and distribution of any large scale die-off events, which in turn can help us determine the cause.”
It is not unusual to see a few dead fishes in inshore areas at this time of year, when the seawater is at its warmest. Increasing temperatures reduce oxygen levels in the water, which affects some species of fish. Further, warmer temperatures promote the growth and reproduction of naturally occurring bacteria, viruses and other parasites that can affect fish health. These fish pathogens are normally present at low levels, and are generally not pathogenic to humans.
The current die-off event is affecting a large number of fishes from a wide range of species. The last time there was a fish die-off on this scale was during September of 2009. At that time, the bacterium Vibrio harveyi and a gill parasite, Brooklynella, were found to be the cause. Neither of these organisms is pathogenic to humans. However, at this stage, it is too early to speculate about possible causes behind the current die-off.
DENR is seeking to acquire specimens of affected fish, particularly any fish that are still alive but have visible signs of ill health. Key signs include sores or lesions on the skin, frayed fins or unusual behavior. Suspect behaviours include swimming slowly, upside down or near the surface, rapid movement of the gill covers, or appearing to gasp at the surface of the water. If a fish can be easily captured with a net or a bucket, then that is usually an indication of ill health. Anyone who is able to provide such a sample should call the Marine Resources Section on 293-5600.
In the meantime, the build up of dead fishes on the shoreline constitutes a public health nuisance because of the odor and the associated insects.
Dead fish on private shorelines should be collected carefully using rubber gloves, placed in a sturdy plastic bag and taken directly to the incinerator at Tynes Bay. It should go without saying that under no circumstances should these fish be eaten, either by people or other animals, regardless of how fresh they might look.
Additional information on this situation will be provided as it becomes available.