Cetacean best practices

MareCet advocates for the utilisation of industrial best practices and aims to assist all interested parties to their implementations. Some of the best practices available include those for the following activities:

1. Seismic-related activities

High intensity underwater noise, such as those emitted during seismic acquisition, a method frequently utilized in oil and gas exploration at sea, can potentially be harmful to marine mammals. At present, it is not a legal requirement under Malaysian law to undertake any mitigation measures to lessen seismic impacts on marine mammals in Malaysian waters. However, the following items are a summary of practices from around the world to mitigate seismic-related impacts to marine mammals:

  • Generally, use the lowest possible power levels throughout the seismic survey and minimize high frequency noises;
  • Appointment of a dedicated and qualified Marine Mammal Observer (MMO) onboard the seismic vessel to coordinate and ensure steps are being taken to reduce potential impacts from survey activities;
  • A pre-survey visual observation to check for the presence of marine mammals within a 1.5km radius of the vessel using binoculars should be conducted at least 30 minutes prior to the use of any high energy acoustic source;
  • At low visibility conditions (i.e. night time, poor weather conditions, etc.) the use of Passive Acoustic Monitoring (PAM) should be considered, if available.
  • Air guns should be fired up one at a time and not at full pressure (i.e. soft start), only when no marine mammals are present in the area;
  • Visual observation should continue throughout the survey period (i.e. when air guns are shooting);
  • A shutdown should be conducted whenever a mother –calf pair is sighted within 1.5km radius of the vessel while survey work is carried out; and
  • All records of marine mammal sightings and survey work procedures should be recorded for continuous data collection and monitoring.

2. Tourism

Encounters with marine mammals can be an exciting event. However, if not handled appropriately, these encounters can be harmful to both the animals and humans. The following are recommended guidelines to minimize any impact that can potentially occur during marine mammal watching events:

  • Be cautious during an encounter. The animals are wild and unpredictable and may not be comfortable with/accustomed to your presence;
  • Reduce boat speed to the same speed of the animals or slower to avoid startling them;
  • Only approach the animals from the side and slightly behind parallel to their travelling direction at the time;
  • Keep clear of the area in front of them at all times and never drive the boat through a school of animals;
  • Do not surround or crowd the animals, and keep viewing to a distance of approximately 100 meters from the animals;
  • Limit encounters to a maximum of 30 minutes to avoid injuries and overcrowding, especially when watching schools containing calves; and
  • Do not, or allow anyone to feed, touch, and swim with the animals.

3. Fishing

Increasing fishing activities and decreasing fish stocks have resulted in high competition between humans and cetaceans for the same resources – fish and other seafood. Fishing activities using nets and hooks present a threat to cetaceans in the sea through entanglement and injuries which often result in death of the inflicted animal(s). Some of the technological advances and best practices may potentially help in mitigating these threats, as follows:

  • Fishers should take great care not to set nets when marine mammals are present in the area;
  • Nets, especially gill nets and purse seines, should not be set at night, especially in areas where dolphins are known to feed;
  • Purse seine operators should install ‘Medina dolphin safety panel’ to reduce the risk of dolphin bycatch; and
  • ‘Weaker’ fish hooks should be used for line fishers to allow the hook to straighten and the dolphins to escape