Perth’s sparkling blue coastal waters are home to significant populations of wild bottlenose dolphins and Australian sea lions. Our local boating community is blessed to enjoy occasional encounters with these fascinating marine mammals and many water users will recall an amazing close encounter where a dolphin or sea lion swam right up to their boat and just sat there. Some of these encounters involve the dolphin lifting its head or maybe its whole body out of the water to get a good look at the passengers onboard, other stories describe the dolphin rolling onto its back to show off its belly or blowing bubbles from its blowhole in the shape of a ring, some people can recall in amazement being able to actually reach out and pat their new found friend. Unfortunately, most of these encounters have a common theme in that the passengers are so impressed that the dolphin or sea lion is rewarded by being handed a fish. Perhaps people would think twice if they understood that their behaviour could actually be killing the animal.
Recent research on the bottlenose dolphin population of Cockburn Sound (Dr Hugh Finn 2005, Murdoch University) found that illegal hand-feeding of local dolphins was a serious threat to their well being. Hand-fed dolphins suffer more boat related injuries (including fin amputations) and fishing line entanglements than non-fed dolphins, and line entanglements are the #1 cause of observed deaths of the local calves. Numbers of hand-fed dolphins have risen from just one dolphin a decade ago, to almost 10% of dolphins in Cockburn Sound. The Department Of Environment and Conservation also estimates that 33% of observed deaths of sea lions are human-related (Dept Environment and Conservation report, 1992).
Hand-fed dolphins suffer more boat related injuries (including fin amputations) and fishing line entanglements than non-fed dolphins
Rockingham Wild Encounters have been running dolphin swimming and watching tours in the waters of Cockburn Sound and the Shoalwater Islands Marine Park since 1989. Owner Terry Howson spent a year researching and building up trust with the local dolphins- the relationship is believed to be a world first in that food was not used as an incentive to coerce the dolphins into unnatural behaviours. His primary objective was not to change anything about the dolphin’s natural behaviours. He never considered offering the dolphins food, as he was concerned that it would be detrimental to the their health and it went against his aim of allowing people to enjoy a truly wild dolphin encounter. Over the years Rockingham Wild Encounters have witnessed first hand the sad consequences of illegal hand feeding and have been developing the Keep Perth's Dolphins and sea lions Wild Project since 2001 to combat the problem.
Rockingham Wild Encounters would like to thank the Australian Government Envirofund for granting funding in 2006 to turn our project into a reality. Australian Government Envirofund is a federal scheme that helps small groups undertake projects to protect local biodiversity and the environment. (For more information go to www.nht.gov.au/envirofund). Rockingham Wild Encounters would also like to thank the Kwinana Industries Council for sponsoring the project. We would also like to thank local marine biologist Rebecca Donaldson whose research and support has been instrumental in getting this project underway.
Hand Feeding Perth’s Dolphins and sea lions is harmful
A recent 10-year study of dolphins in Cockburn Sound found that illegal feeding by the public has had a range of harmful effects. (The study, by Murdoch University biologists Hugh Finn and Bec Donaldson, is reported in Dr Finn’s 2005 PhD thesis). The major negative impacts suffered by dolphins that have learnt to beg include:
- Increased rates of boat propeller strikes and fishing line entanglements resulting in injuries and fin amputation.
- Abnormal risky behaviour. Begging dolphins stay dangerously close to boats and high-boat use areas, as well as areas where lethal fishing line is concentrated.
- Breakdown of normal social behaviour, including breakdown of male bonds with other males, which are critical for obtaining mates.
- Dramatic changes to ranging patterns, including spending hours waiting at boat ramps and jetties, instead of in their previous home-range areas with other dolphins.
- Abnormal feeding patterns. Begging dolphins spend less time hunting their own food (which, for young dolphins, may mean they do not develop hunting skills). Instead, they risk eating contaminated or inappropriate handouts from humans.
- Increased likelihood of becoming solitary loners, increasing their risk of shark attack.
- Passing on the dangers to their young. At least one female that became a beggar has had a calf that has also become a beggar. At Monkey Mia, calves of hand-fed females had higher death rates than other calves, until tighter management practices were put in place.
HOOK — The true story of a dolphin that became a beggar
Hook was a typical adult male bottlenose dolphin living in Cockburn Sound. We know details of his life and what happened to him because marine biologists have been studying him and the other local dolphins for over 10 years. Hook was a member of a long-term partnership or 'alliance' with two other males. He was inseparable from his two alliance partners, spending over 95% of his time with them. Like other males in Cockburn Sound, Hook had likely developed this partnership during his teenage years, and such partnerships can last the males' entire lives. In cooperation with his two partners, Hook competed for females against rival male alliances in Cockburn Sound. He and his alliance partners were likely in their 20s (the prime for male bottlenose dolphins) due to their success at obtaining females. Hook also hunted and caught his own fish and squid, and his home range was confined to Cockburn Sound.Hook started being fed by recreational fishers in 2000 — his behaviour changed dramatically. First, his home range and movement patterns became abnormal. He began spending hours at boat ramps and jetties, and started leaving Cockburn Sound to travel alone as far north as Fremantle to beg from boats. This was twice as far as any other Cockburn Sound dolphin had been seen to travel. At the same time, Hook experienced a breakdown in his long-term alliance.
As a chronic beggar, Hook faces increased of injury and death from boat strikes, fishing line entanglements, and deliberate attack from humans
He became a loner, socially isolated from his previous alliance partners and other dolphins. Adult male dolphins in Cockburn Sound depend on their alliance partners to help them compete against rival males for females, and also perhaps for protection against sharks. It is likely that Hook is now facing reproductive failure and increased risk of shark attack. His former alliance partners have also probably suffered negative consequences — without him they will be weaker and less competitive against rival males. As a chronic beggar who now spends much of his time at jetties and following boats, Hook’s new lifestyle will prevent him from ever forming new close social bonds. He also faces increased risk of eating contaminated, rotten or inappropriate foods, and increased risk of injury and death from boat strikes, fishing line entanglements, and deliberate attack from humans, as have befallen other dolphins in Cockburn Sound.
Our project’s purpose is to help protect Perth’s marine wildlife.
Raising public awareness
We intend to reduce the incidences of human related dolphin and sea lion deaths or injuries through a public awareness campaign targeted at current water users and school children- the next generation of water users. In particular we will draw attention to the two main threats posed by water users:
- The hand feeding of dolphins and sea lions
- The discarding of fishing line and other rubbish at sea
Our public awareness campaign will include interpretive signs at popular boat ramps and other key locations, distributing informational pamphlets direct to water users on site at boat ramps and educational briefings to local schools and stakeholder groups. Media coverage will also be sought through local newspapers, television and radio contacts.
Research and monitoring
Ongoing research will be conducted by Rockingham Wild Encounters during tours. Staff will record incidences of begging dolphins and sea lions and incidences of hand feeding. This research will be used to measure the effectiveness of our public education campaign.
A marine mammal response and rescue team has been established from amongst the crew of Rockingham Wild Encounters. The team is trained and insured to handle marine mammal rescues. This will enable staff to undertake rescues on site during tours under guidance of wildlife authorities who are often unable to get to the site quickly enough to undertake a rescue.