Africa-Press – Mozambique. It all started on the 7th of September, when, at around 6:00 a.m., a juvenile Orca whale measuring 5.5 metres was sighted on Barra beach, found at high tide of the spring tide completely exposed and approximately 50-75 m from the sea. tide line.
According to a statement sent by the Mega Fauna organization, initially a team of four people tried to push the animal back into the water, but were not sure how to do this and needed additional support.
A few hours later, at approximately 9:20 a.m., a support team began to mobilize and move the animal. Meanwhile, between 7:00a.m. and 9:00a.m., police officers from the local post arrived to control the situation and there was some talk about the response protocol and the urgency of the situation to try to get the animal back into the water as soon as possible.
At around 9:20 a.m., despite uncertainties with official authority and protocol, the Barra community quickly assembled a response team with tractor and rollers to mobilize the animal and return it to the water, but it was already out of the water for three or four hours.
This response facilitated the animal’s return to shallow water. It was then helped to move off the coast (southwest of the initial stranding site), where it ran aground on a shallower sandbank and remained half-submerged, half-exposed to the sun.
At around 10:00 a.m., marine biologists assessed the situation and, in collaboration with fisheries officials, decided that the best decision was to allow the animal some rest time in shallow water while the tide was still low and access to canals deeper and in open sea was restricted.
Biologists checked the animal for important external injuries to assess the body condition, of which only superficial cuts and scratches were detected. The animal’s dorsal surface was covered and kept wet to avoid sunburn and the animal remained in this position in shallow water, resting, for approximately two to three hours.
When the tide started to rise, the currents and the water level began to rise. The shade cloth was removed from the animal and the orca moved to a little deeper water, where it remained in a passive state, using its tail and pectoral fins to remain upright to allow easy breathing without expending high energy levels. .
This was a preliminary indicator that the animal was not in good health despite the initial stranding. The orca was observed from boats and encouraged to swim further towards the mouth of the estuary, using a boat to block access to the estuary.
The statement, which we have been quoting, indicates that the currents were pushing the animal in the opposite direction (towards the estuary) and it was moving passively, swimming and maintaining a stationary or floating position with the current. The animal showed very moderate dodge or lean response to its steering path being actively blocked – a secondary indicator that the animal was not in good health.
In deeper sections of water, the animal was seen to display more swimming ability, but actively choosing to rest on shallower shores.
At approximately 3:30 p.m., when tidal levels were quite high, the animal moved from the shallow water bank to a section of the estuary with many permanent prawns traps.
The animal rolled sideways over the outer fence of the fish trap and entered the trap. This prevented the boat from having more access to help guide or protect the animal, so the decision was made to switch to shore operations.
The animal was stationary at a position approximately 200 metres from the shore at the edge of the mangroves near Barra. At this point, the orca is estimated to have moved approximately 3 km away from the initial stranding site further into the estuary.
A team was mobilized from a high vantage point to watch the whale as the boat team returned to shore and moved to another point, from which a group of four kayaks mobilized to watch the whale as fishermen came closer and closer to the animal.
The kayak team stayed with the animal until nightfall. Before that, a sailing boat had anchored beside the animal to help the group of kayaks, and two others were ready and waiting 200m away, on the edge of the mangroves.
Two police officers were at the scene and spoke to the fishermen and sailboat owners, guiding them to leave the animal alone and discouraging them from poaching protected species and explaining the potential health risk of consuming the animal and the danger to fishermen being in the water around the animal or carcass due to increased shark activity in the area.
A growing crowd gathered in the nearby village. Police officers left the site at 5:00 p.m. and the kayak team stayed with the whale until it was completely dark. None of the vessels were properly equipped for night operations and the kayak team returned to shore due to safety constraints.
The orca was monitored from the shore until approximately 8:30 p.m., from where its breathing could be heard. After approximately 9:00 p.m., the animal’s status could not be confirmed, however its last known position was on a tidal flat that is completely exposed during low tide, at 11:48 p.m..
It so happens that, on the following day, September 8, the morning investigations began as early as dawn and various parties were involved in determining the location and condition of the animal.
A boat search was carried out around 6:00 a.m. in an attempt to locate the animal. In parallel operations, a search was carried out on the coast by means of a quad bike to look for signs of stranding or confirm a carcass, but nothing was detected at sea or on the coast.
Communications with local leaders and police and fisheries officials were made in an attempt to confirm rumours that the animal was dead and the carcass had already been scavenged by local communities on the mainland and nearby islands for its meat.
At this stage, the cause of death of the animal and the reason for the original stranding behaviour remained unclear. The community leader provided an escort and authorised the research team to inspect the carcass and perform an opportunistic necropsy on the animal.
The unconfirmed history of the carcass at this stage is that half was retained for the community closest to where the animal was last seen alive, the other half was towed by a sailing boat and taken to nearby islands. Each half of the carcass was distributed among the communities.
Meat-selling anecdotes were reported on the islands early in the morning, but this could not be confirmed by authorities during a site visit later in the day.
The partial remains of the animal were found approximately 1.5 km away from the last point where the animal was observed alive.
The animal’s head and half of the vertebrae were left in the intertidal zone.
By the time the researchers arrived at the scene, the carcass had been stripped of meat and it appears that the liver was also harvested.
Some of the other internal organs remained in place, scattered in the sand around the carcass.
The team managed to collect some skin, fat and kidney samples from the remains. The lungs and intestines were inspected for cysts and parasites. Inspection of the intestines shows that the upper and lower sections were filled with long parasitic tapeworms, approximately 1.5m in length, and it seems possible that the parasitic load in the intestines may have contributed to the animal’s poor health, although this has not yet been verified.
The Mega Fauna communiqué also mentions that a sample of the parasites was collected for further investigation. A section of the jaw and teeth were collected, with three of the vertebrae.
All samples were collected to provide a better understanding of the animal’s condition and will be added to the database set on the behaviour and movements of orcas in tropical waters in the southwestern Indian Ocean.
Biologists involved in the operation warn of health risks for people who may have consumed the animal’s meat or been in direct contact with the carcass remains without the proper protective equipment (i.e. masks and gloves).
They also warn that increased shark activity can be expected in the area as carcass continues to decompose. Water users should be careful and are discouraged from entering the surrounding waters during high risk times of the day (i.e. sunset, sunrise, cloudy water and being alone) for the next 7 to 10 days.
By
Hugo Firmino
