Saving the Whales

With a widespread global commercial maritime traffic, there has been an increasing number of collisions between whales and boats, leading to many whale injuries and deaths.

Because of unregulated shipping patterns and lack of legislation and supervision, this is a chronic problem in many areas of the world.

However, in this blog I’ll talk about an inspiring success story of harnessing scientific research to change maritime regulations and protect the whales.

Special Habitat

Thanks to Panama’s unique weather, the country hosts a variety of habitats with rich flora and fauna. The Gulf of Panama, on the pacific side of the Panama Canal, has warm and rich waters, offering a refuge for the southern hemisphere’s mighty whales, where hundreds of humpback whales gather to feed and mate. Humpbacks migrate northwards from their summer feeding grounds around Antarctica, arriving in the region around late June. They breed in the fertile Las Perlas waters, where an upwelling of nutrient-rich water produces an annual plankton bloom. Altogether, about 900 animals are thought to be involved. There are also visitors from a Northern Hemisphere humpback population.

The Canal

Panama is also famous for its canal, and the Gulf of Panama is the Pacific end of the Panama Canal. About 17,000 large ships pass through Panamanian waters each year, the majority international cargo vessels using the canal. This shipping superhighway sees more than 36 ships ply its waters each day, including massive cargo vessels weighing hundreds of thousands of tonnes. Until recently, unregulated shipping patterns caused whales and ships to frequently collide, damaging vessels and injuring or killing the animals. From 2009 to 2012, there were 13 whale deaths in the gulf, many thought to be the result of ship strikes. Data shows one particular vessel routinely passing right through the Las Perlas protected area in order to excavate sand from the sea bed and bring it to land for construction.

STRI — The Smithsonian Tropical Research Institute

STRI is the only bureau of the Smithsonian Institution based outside of the United States, in Panama. It is dedicated to understanding the past, present and future of tropical ecosystems and their relevance to human welfare. Héctor Guzmán, a marine biologist at the Smithsonian Tropical Research Institute in Panama, led a research that was crucial to the development of the new regulations to protect the whales.

Guzmán’s research focuses on highly migratory species including whales, manatees, sharks, sea birds, billfishes and turtles to better understand their basic ecology and to encourage scientifically supported conservation policies. A major challenge in this endeavor is, as Guzmán’s states:

“Rapid change and lack of pristine marine environments skew basic research. Instead of studying tropical systems unchanged for millennia, scientists must ask questions about ongoing human impacts and conservation to inform policy.”

The Research

“This started as basic, fundamental research,” Guzmán says. The next step was to find partners to do something about it. Guzmán worked with Panama Canal pilot Fernando Jaén, the Panama Canal Authority, and a range of other stakeholders for two years to refine a proposal to keep ships away from the majority of the known whale concentrations.

Similar to how roads are now sometimes built to curve around the natural habitats of land creatures, Traffic Separation Schemes (TSS) create shipping lanes that restrict marine traffic to certain areas. But in order to get all shipping to abide by this system, countries need the approval of the International Maritime Organization (IMO), a UN body that regulates shipping safety and navigation around the world.

So Guzmán and his colleagues began to use satellite beacons to track 15 humpback whales in the Gulf of Panama, and overlaid their tracks with transit records for nearly 1,000 ships. They found that because there was no set path for ships to take as they entered the canal, whales and ships frequently came into contact. Further research showed that during one 11-day period, whales and ships moved within 200 meters of each other 98 times.

Solution and Legislation

In 2013, the proposed TSS was submitted to the IMO. The proposal was adopted in December 2014, and global shipping charts were updated to reflect the now-mandatory shipping lanes. The IMO also requires ships to move no faster than 10 knots in the area from August to November, when humpback whales tend to congregate in the gulf.

Fortunately, the combination of solid whale biology and regulations passed by the IMO has resulted in a scheme that has lessened the frequency of those ship strikes; these regulations are estimated to have cut the potential for whale strikes by as much as 92 percent. Guzman is now using his whale biology studies and the lessons learned from the Panama project to help create similar schemes all along the Pacific coast.

Digging Deeper into the Data Science behind the Research

Time period: 2003 to 2009

Area: Las Perlas Archipelago off the Pacific coast of Panama

Observations: 53 times between the months of August and October

Main goals:

1. To estimate the size of the humpback whale population at Las Perlas Archipelago in Pacific Panama.

2. To gain a better understanding of the migratory connections between the whales from the Southern Hemisphere.

3. To acquire the knowledge needed to determine if protection is warranted for the species in Panama from the effects of increasing coastal development, maritime traffic, and tourism.

Identification / Classification:

1. We identified 295 individuals using photo-identification of dorsal fins, including 58 calves, and the population estimate for a single season was 100–300 solitary adults plus 25–50 mothers with calves; the estimated population of animals across all seasons using a mark and recapture model was over 1,000.

2. Eight of the 139 fluke identifications were matched to whales in photograph catalogues from the Antarctic Peninsula and a ninth was matched to a whale sighted in Chilean waters; four of these nine individuals have also been sighted in Colombia.

3. We conclude that Panama (Las Perlas Archipelago in particular) is an important calving area for humpback whales in the Southern Hemisphere. These data should provide a foundation for monitoring of population change and to increase awareness in Panama about the need to manage vessel traffic and tourism related to the whales at Las Perlas.

Methods:

Study Area and Photo-identification / Classification:

• 168,771 ha, of which 135,618 ha are marine environments.
• averaging 15 m depth and all <50 m.

Site preference and whale distribution within the archipelago:

• carried out with monthly aerial surveys (was not used in any population analyses)

Whales were photographed for later identification using ventral fluke and dorsal fin marks:

• Images catalogued with IMatch3. The flukes and dorsal fins were first compared internally for each year, then compared externally.

Whale Satellite Tracking:

Real-time satellite transmitters, constant transmission.

We used tag-derived positions from Argos location classes 3, 2, 1, 0, A, and B, providing positional errors of 150 m to 5 km radius.

The open-population mark-recapture model:

• A sample of 295 individuals (based on the photo-identifications)
• Daily sighting histories were constructed for those animals,
• 50 observation days over the 5 yr
• Data are vectors of length 36,
  1 = days it was photographed
  0 = on days it was not.
• Animals known by flukes alone were excluded because they might overlap with those known by dorsal fin alone.
• The sighting histories formed the basis of an analysis of population size and residency, using the Cormack-Jolly-Seber mark-recapture method.

Estimating population size requires estimating first two key parameters:

1. The probability dt of detecting an animal in the study area on day t,

2. the probability et that an animal in the study area on day t departs before day t+1.

The standard method is to find parameters which best account for observations based on maximum likelihood.

We used a Bayesian method, based on the same likelihood formulations but producing also 95% credible intervals for every parameter, and we employed a multilevel, hierarchical model, in which daily variation in the parameters was permitted but constrained to follow overarching hyperdistributions. This improves statistical power relative to unconstrainted day-to-day variation.

Results and Discussion

• Sightings and Resightings: we identified 295 distinct animals based on dorsal fin markings, including 185 solitary adults, 52 mothers (with a calf), and 58 calves (with a mother). — table 2

• Migratory Connections: Panama is an important breeding area for some whales feeding in Chile. Fig 2
• Capture-recapture Estimate: by pooling our data across seasons, we estimated that the population size at Las Perlas is just over 1,000 animals.
• Further collaborative studies are needed to provide better estimates of population size in Pacific Panama, and long-term monitoring is essential in order to detect and understand changes and potential risks to the population, particularly calf production. Our current study provides an antecedent to such monitoring.