Basking Shark Migration
Basking shark migration represents one of the ocean’s most impressive yet mysterious journeys, with individuals traveling up to 9,600 kilometers (5,965 miles) between seasonal habitats. These gentle giants—the world’s second-largest fish—undertake extensive migrations driven by plankton availability, water temperature, and possibly reproductive behavior, moving from summer feeding grounds in temperate coastal waters to winter destinations ranging from deep offshore waters to distant southern latitudes.
For decades, the winter whereabouts of basking sharks puzzled scientists, with early theories suggesting hibernation in deep water or disappearance to unknown locations. Modern satellite tracking technology has revolutionized understanding of basking shark migration patterns, revealing extraordinary behavioral diversity with individual sharks adopting different strategies—some staying local, others migrating thousands of kilometers south, and a few crossing entire ocean basins in trans-Atlantic journeys.
This comprehensive guide explores everything currently known about basking shark seasonal movement, including why they migrate, where they go, how far they travel, regional pattern variations, vertical depth migrations, latest tracking research from 2025-2026, and what these movements mean for conservation efforts protecting these endangered filter feeders.
Basking Shark Migration: Quick Facts
Key Migration Statistics: ✓
Distance: 1,000-9,600 km (620-5,965 miles) typical range ✓
Longest Recorded: 9,589 km (5,958 miles) – British Isles to Newfoundland ✓
Duration: Satellite tags tracked sharks for 165-479 days ✓
Speed: Average 1-3 mph during migration; maximum 5 mph ✓
Depth Range: Surface to 1,264 meters (4,147 feet) during migration ✓
Seasonal Timing: Depart feeding grounds September-November; return March-May
Migration Patterns:
✓ Three main strategies: Stay local, medium-distance (1,000-2,000 km), long-distance (3,000-9,000+ km) ✓ Individual variation: Not all sharks follow same pattern ✓
Year-to-year variation: Unknown if individuals repeat same migration annually
Why Do Basking Sharks Migrate?
Following Plankton Blooms
The primary driver of basking shark migration is food—specifically, seasonal changes in plankton abundance and distribution.
Plankton-Driven Movement: Basking sharks are obligate planktivores requiring approximately 2,000 pounds (900 kg) of zooplankton daily. Plankton productivity varies dramatically by season and location:
Spring/Summer (April-August):
- Temperate coastal waters experience massive phytoplankton blooms
- Phytoplankton supports zooplankton (copepods, barnacle larvae, fish eggs)
- Surface waters (0-30 feet) contain dense plankton concentrations
- Sharks aggregate in productive feeding grounds (Scotland, Ireland, Canada, California)
Autumn/Winter (September-March):
- Surface plankton abundance crashes as temperatures drop and sunlight decreases
- Coastal plankton productivity declines dramatically
- Many zooplankton species descend to deeper waters or migrate southward
- Sharks must relocate to find adequate food
Migration as Foraging Strategy: Basking sharks don’t migrate randomly—they track plankton resources, moving to regions and depths where zooplankton remains abundant year-round.
Temperature Preferences and Tolerance
Water temperature influences basking shark distribution, though recent research shows greater thermal tolerance than previously believed.
Preferred Temperature Range: 8-14°C (46-58°F)
Tolerance Range: -0.6 to 29.9°C (31 to 86°F) –
one of the widest thermal ranges for any shark species
Recent 2025 research on Arctic Circle basking sharks revealed individuals tolerating water as cold as -0.6°C (31°F), dramatically expanding known thermal limits. This suggests temperature may be a secondary migration driver rather than primary cause, with plankton availability being more important.
However, temperature still influences migration timing:
- Sharks often depart feeding grounds when surface temperatures drop below 10°C (50°F)
- Southern winter destinations offer warmer waters (14-20°C/57-68°F)
- Some sharks specifically seek temperature fronts where different water masses meet, concentrating plankton
Reproductive Behavior (Hypothesis)
Scientists hypothesize that reproduction may drive some basking shark migration patterns, though this remains largely unproven due to difficulty observing mating.
Reproductive Migration Theory:
- Mating likely occurs during spring/summer aggregations in coastal waters
- Pregnant females (2-3.5 year gestation) may seek specific birthing areas
- Pup birth might occur in warmer southern waters during winter
- Males and females may segregate during winter months
Evidence:
- Some tagged females showed different migration patterns than males
- Pregnant females might have different nutritional needs
- Deep-water winter migrations could provide protection for pregnant females
Current Status: Unconfirmed—more research needed to establish reproductive drivers.
Seasonal Migration Patterns Explained
Spring Migration (March-May)
Northward and Coastal Movement: As spring arrives and day length increases, basking sharks begin returning to productive temperate coastal feeding grounds.
Key Spring Behaviors:
- Timing: First arrivals typically March in southern regions, April-May further north
- Direction: Generally northward from winter locations
- Destination: Continental shelf waters where spring plankton blooms developing
- Depth: Transitioning from deep winter habitats to shallow feeding areas (0-100 feet)
- Aggregation: Initially scattered; concentration increases as plankton blooms intensify
Spring Triggers:
- Increasing day length (photoperiod)
- Rising water temperatures
- Developing phytoplankton blooms
- Zooplankton population growth
Summer Aggregations (June-August)
Peak Feeding Season: Summer represents the pinnacle of basking shark seasonal movement, with maximum numbers concentrated in known feeding hotspots.
Summer Characteristics:
- Location: Coastal shelf waters (Scotland, Ireland, Cornwall, Canada, California, etc.)
- Behavior: Extensive surface feeding in plankton-rich waters
- Aggregations: Groups of 3-100+ sharks in exceptional plankton patches
- Depth: Primarily shallow (0-100 feet) but with occasional deeper dives
- Duration: Typically 3-4 months of consistent presence
Summer Hotspots:
- Scotland: Inner Hebrides, Isle of Skye, West Coast
- Ireland: West Cork, Kerry, Clare
- England: Cornwall, Isle of Man
- Canada: Bay of Fundy, Nova Scotia, Newfoundland
- United States: New England, California (Monterey Bay)
- Norway: Northern coast including Arctic regions
Autumn Departure (September-November)
Southward or Offshore Migration: As autumn progresses, plankton abundance declines and basking sharks begin departing summer feeding grounds.
Autumn Migration Timing:
- Early Departures: Some individuals leave by late August
- Peak Departure: September-October
- Late Stragglers: Occasional sightings through November
- Variation: Individual timing varies by 4-8 weeks
Departure Triggers:
- Decreasing day length
- Declining water temperatures (below 10-12°C/50-54°F)
- Reduced surface plankton abundance
- Possibly reproductive status
Migration Direction: Three primary autumn strategies:
- Stay Local: Remain in UK/Ireland region, move to deeper water
- Medium-Distance South: Migrate to Bay of Biscay (500-1,500 km)
- Long-Distance South: Travel to Portugal, North Africa, or further (2,000-4,000+ km)
Winter Distribution (December-February)
The “Missing” Season: For over a century, basking sharks seemed to vanish during winter, leading to hibernation theories. Modern tracking reveals the truth: they’re active but difficult to observe.
Winter Strategies:
Strategy 1: Local Deep-Water Residents
- Remain in UK/Ireland/North Sea region
- Dive to depths of 600-3,000 feet (200-900 meters)
- Feed on deep-water zooplankton
- Rarely surface (hence “disappearance”)
- Duration: Entire winter (December-March)
Strategy 2: Bay of Biscay Migration
- Travel 500-1,500 km south to France/Spain offshore waters
- Occupy mid-depth and deep waters
- Warmer temperatures (12-16°C/54-61°F)
- Productive deep-water plankton
Strategy 3: Southern Migration
- Long-distance travel to Portugal, Azores, Mediterranean, North Africa
- Some individuals reach waters off Canary Islands, Morocco
- Distances of 2,000-4,000+ km from summer grounds
- Combination of surface and deep-water behavior
Strategy 4: Trans-Atlantic Migration (Rare)
- A few individuals cross entire Atlantic Ocean
- Documented migrations: British Isles → Newfoundland (9,589 km)
- Also: New England → Caribbean, Bahamas, South America
- Some sharks cross equator into Southern Hemisphere
Where Do Basking Sharks Migrate? Routes & Distances
Northeast Atlantic Migration Routes
Primary Documented Routes:
Route 1: Scotland/Ireland → Bay of Biscay
- Distance: 800-1,500 km (497-932 miles)
- Direction: South along European continental shelf
- Duration: 2-4 weeks travel time
- Frequency: Common pattern (30-40% of tagged sharks)
Route 2: Scotland/Ireland → Iberian Peninsula & North Africa
- Distance: 2,000-3,500 km (1,243-2,175 miles)
- Direction: South-southwest to Portugal, Morocco
- Stops: Some pause in Bay of Biscay before continuing
- Duration: 4-8 weeks
- Frequency: Moderate (20-30% of tagged sharks)
Route 3: Local Residency
- Distance: 0-500 km from summer grounds
- Pattern: Remain in UK, Ireland, Faroe Islands, North Sea
- Depth Change: Move from shallow to deep water (600-3,000 feet)
- Frequency: Common (30-40% of tagged sharks)
Western Atlantic Migration Routes
Route 4: New England → Mid-Atlantic/Caribbean
- Distance: 1,500-4,000 km (932-2,485 miles)
- Direction: South-southeast
- Destinations: North Carolina, Bahamas, Caribbean Sea
- Behavior: Extensive mesopelagic diving (500-1,000 meters)
- Notable: Some sharks cross equator to South America
Route 5: Canadian Maritimes → Southern Waters
- Distance: Variable, 1,000-3,000 km
- Pattern: Along eastern North American continental shelf
- Winter Locations: Mid-Atlantic, Gulf Stream waters
Trans-Atlantic Crossings
Epic Migrations: The longest recorded basking shark migration involved a shark tagged off the Isle of Man (British Isles) that traveled 9,589 km (5,958 miles) to Newfoundland, Canada—a true trans-Atlantic crossing.
Trans-Atlantic Characteristics:
- Duration: 82-120+ days for crossing
- Route: Deep ocean, not following coastlines
- Depth: Extensive mesopelagic diving (400-1,264 meters)
- Frequency: Rare—only handful of documented cases
- Purpose: Unknown (possibly following deep-water plankton, reproductive areas, or historical population connectivity)
Migration Distance Summary
| Migration Type | Distance | Example Route | Frequency |
| Local | 0-500 km | Scotland → deeper North Sea | 30-40% |
| Medium-Range | 800-2,000 km | Ireland → Bay of Biscay | 30-40% |
| Long-Range | 2,000-4,000 km | Scotland → North Africa | 20-30% |
| Trans-Atlantic | 5,000-10,000 km | UK → Canada | <5% (rare) |
Median Migration Distance: 3,633 km (2,257 miles) based on satellite tracking studies Median Displacement: 1,057 km (657 miles) from tagging location
Winter Migration: Where Do They Go?
The question “where do basking sharks migrate in winter” now has multiple answers thanks to satellite tracking research.
Portugal and North Africa (Southern Destinations)
Geographic Range:
- Portuguese coast (Lisbon to Algarve)
- Azores Islands
- Canary Islands
- Morocco and Western Sahara coast
Winter Behavior in Southern Waters:
- Combination of surface and deep-water feeding
- Water temperatures: 14-20°C (57-68°F)
- Duration: December through March
- Some sharks remain for entire winter; others continue moving
Why These Regions?
- Year-round plankton productivity in productive upwelling zones
- Warmer water temperatures
- Possible reproductive/mating areas
- Historical population connectivity
Bay of Biscay (Mid-Distance Destination)
Location: Offshore waters between France and Spain
Characteristics:
- Distance from UK/Ireland: 800-1,500 km
- Water depth: 100-4,000 meters (continental shelf to deep basin)
- Winter temperatures: 12-16°C (54-61°F)
- Productive frontal zones where Atlantic meets European shelf
Shark Behavior:
- Mix of surface and deep diving (200-800 meters typical)
- Feeding on deep-water zooplankton
- Duration: Full winter or 1-2 months before moving further south
UK and Ireland (Stay-at-Home Strategy)
Local Winter Residents: Approximately 30-40% of tagged sharks don’t migrate far from summer feeding grounds, instead remaining in UK, Ireland, North Sea, or Faroe Islands waters.
Deep-Water Winter Behavior:
- Depth Range: 600-3,000 feet (200-900 meters)
- Surface Appearances: Rare (explains historical “disappearance”)
- Feeding: Active on deep-water zooplankton communities
- Duration: Continuous deep residency December-March
- Advantage: Minimal energy expenditure on migration
Recent 2025 Arctic Research: Studies on basking sharks north of Arctic Circle revealed individuals spending winter in extreme conditions:
- Water temperatures below 5°C (41°F), some as cold as -0.6°C (31°F)
- Extended periods in polar night darkness
- Deep diving below 800 meters for weeks
- Demonstrates extreme environmental tolerance
Tropical and Equatorial Waters (Western Atlantic)
Caribbean and South American Migrations: Some Western Atlantic basking sharks migrate to tropical regions previously thought inhospitable:
Destinations:
- Bahamas
- Caribbean Sea
- Coast of South America
- Record: Some crossed equator into Southern Hemisphere
Surprising Behavior:
- Extended periods at mesopelagic depths (500-1,000 meters)
- Weeks to months at depth without surfacing
- Tropical surface waters avoided (too warm, low plankton)
- Deep tropical waters contain productive zooplankton communities
Significance: Demonstrates basking sharks are not restricted to temperate latitudes—they exploit deep-water tropical habitats accessible through vertical migration.
Summer Migration and Feeding Grounds
Scotland and Ireland (Prime Feeding Destinations)
Why Scotland/Ireland? These regions host some of the world’s most important basking shark summer feeding grounds:
Scottish Hotspots:
- Inner Hebrides (Coll, Tiree, Mull, Skye)
- West Coast mainland waters
- Firth of Clyde
- Oban region
Irish Locations:
- West Cork (prime viewing area)
- Kerry Peninsula
- Clare Coast
- Donegal waters
Optimal Conditions:
- Massive spring/summer plankton blooms
- Nutrient-rich waters from Atlantic currents
- Productive frontal zones
- Continental shelf habitat
- Water temperatures 10-14°C (50-57°F)
Peak Season: May through August, with June-July representing maximum abundance
Canadian Maritime Waters
Major Summer Destinations:
- Bay of Fundy (Nova Scotia/New Brunswick)
- Nova Scotia Atlantic coast
- Newfoundland offshore waters
- Gulf of St. Lawrence
Characteristics:
- Cold, productive waters (8-14°C/46-57°F)
- Massive tidal mixing (especially Bay of Fundy)
- Rich plankton communities
- Some sharks remain June-September
California and Pacific Coast
Monterey Bay: The most significant Eastern Pacific basking shark feeding ground, famous for:
- Deep underwater canyon creating upwelling
- Year-round plankton productivity
- Cool California Current waters
- Peak sightings April-September
Other Western U.S. Locations:
- Northern California coast
- Oregon (occasional)
- Washington (rare)
Other Global Summer Grounds
- Norway: Including Arctic Circle regions
- Iceland: North coast
- New Zealand: Southern waters
- South Africa: Cape waters
- Southern Australia: Tasmania region
How Scientists Track Basking Shark Migration
Satellite Tag Technology
Pop-Up Archival Transmitting Tags (PSAT/PAT Tags): The primary tool for studying basking shark migration patterns.
How PSAT Tags Work:
- Attachment: Tag attached to dorsal fin or near dorsal area
- Data Recording: Records depth, temperature, light level continuously
- Programmed Release: Detaches after pre-set period (180-365 days typical)
- Surface Transmission: Floats to surface and transmits data to satellites
- Data Analysis: Scientists reconstruct migration routes and behavior
Data Provided:
- Geographic location (geolocation based on light levels and sea surface temperature)
- Depth profile (vertical movements)
- Water temperature at various depths
- Time at depth (surface vs deep water)
- Migration routes (approximate)
Tag Limitations:
- Geolocation accuracy: ±50-150 km (less precise than GPS)
- Premature detachment (animals rub tags off)
- Transmission failure (20-30% don’t transmit successfully)
- Battery life limits deployment duration
SPOT Tags (Real-Time Tracking)
Smart Position or Temperature Transmitting Tags:
- Transmit when shark surfaces
- Provide real-time location (within hours)
- Track surface-swimming sharks continuously
- Limited use for basking sharks (minimal surface time in winter)
Geolocation Technology
Light-Level Geolocation: Uses day length and solar noon timing to estimate latitude and longitude:
- Sunrise/sunset timing determines longitude
- Day length determines latitude
- Sea surface temperature helps refine location
- Accuracy: ±50-150 km
Modern Improvements (2025 Research):
- Machine learning algorithms improve geolocation accuracy
- Integration of oceanographic models
- Behavioral state modeling
- Accuracy improving to ±25-50 km
Latest Research Findings (2025-2026)
Arctic Circle Study (2025): Year-long PSAT deployment on Norwegian sharks revealed:
- Contrasting individual strategies (one migrated to Azores, other stayed Arctic)
- Temperature tolerance to -0.6°C (31°F)
- Extended polar night feeding
- Behavioral plasticity across environmental extremes
Northeast Atlantic Studies:
- 70 satellite tags deployed 2012-2015
- 28 provided data >165 days
- Median tracking: 281 days
- Median distance traveled: 3,633 km
- Three distinct migration strategies confirmed
Western Atlantic Research:
- Transequatorial migrations documented
- Mesopelagic tropical habitat use confirmed
- Deep-diving behavior in warm waters
- Some individuals crossed equator to Southern Hemisphere
Regional Migration Patterns
Northeast Atlantic Patterns
Characteristics:
- Three distinct strategies: local, medium, long-distance
- Post-summer southward movements (October onwards)
- Variable individual behavior (not all sharks follow same pattern)
- Strong site fidelity to summer feeding grounds
- Winter distribution: 33°N to 61°N latitude (3,100 km range)
Sex Differences:
- Possible female/male segregation during winter (under investigation)
- Pregnant females may have different migration patterns
- Insufficient data currently to confirm sex-based differences
Northwest Atlantic Patterns
Characteristics:
- Spring/summer feeding: New England, Canadian Maritimes
- Autumn departure: September-November
- Long-distance migrations common (1,500-4,000+ km)
- Some trans-equatorial movements to Caribbean, South America
- Extensive mesopelagic diving behavior
Arctic Populations
Recent Discoveries:
- Year-round presence in Arctic/sub-Arctic waters
- Winter survival in near-freezing water (-0.6°C to 5°C)
- Extended polar night periods
- Deep-water feeding during winter darkness
Depth and Vertical Migration
Surface Feeding Depth
Summer Feeding:
- Typical: 0-30 feet (0-10 meters)
- Maximum light penetration zone
- Peak plankton concentration
- Most visible to observers
Mesopelagic Diving
Deep Migration Depths:
- Typical Deep Dives: 200-800 meters (656-2,625 feet)
- Extended Deep Periods: Weeks to months at 400-1,000 meters
- Record Depth: 1,264 meters (4,147 feet) – deepest recorded for any basking shark
- Frequency: Common during winter, occasional in summer
Why Dive Deep?
- Access to deep-water zooplankton communities
- Mesopelagic plankton abundance (copepods at 400-1,000m depths)
- Thermal refuge (stable temperatures)
- Predator avoidance (minimal threats at depth)
Diel Vertical Migration
Day/Night Depth Patterns: Many tagged sharks show daily vertical movement cycles:
Daytime:
- Deeper depths (400-800 meters average)
- Following vertically migrating zooplankton
- Cooler, darker waters
Nighttime:
- Shallower depths (200-400 meters)
- Plankton rises toward surface at night
- Following prey movements
Pattern Strength: Varies by individual and season; strongest during trans-Atlantic deep-water migrations
Frequently Asked Questions About Basking Shark Migration
1. Where do basking sharks migrate in winter?
Basking sharks exhibit three main winter migration strategies based on satellite tracking data: (1) Some migrate south 2,000-4,000 km to Portugal, Azores, Mediterranean, and North Africa where waters are warmer (14-20°C) with year-round plankton; (2) Others travel 800-1,500 km to the Bay of Biscay off France/Spain; (3) Approximately 30-40% remain near UK, Ireland, and North Sea but dive to deep waters (600-3,000 feet) to feed on deep-water zooplankton. Individual sharks show behavioral plasticity, not all following the same pattern. Recent research also documents rare trans-Atlantic migrations and tropical deep-water migrations in Western Atlantic populations.
2. How far do basking sharks migrate?
Basking sharks migrate 1,000-9,600 kilometers (620-5,965 miles) between seasonal habitats, with significant individual variation. Satellite tracking studies show a median migration distance of 3,633 km (2,257 miles) with median displacement of 1,057 km (657 miles) from tagging locations. The longest documented migration was 9,589 km (5,958 miles) from the British Isles to Newfoundland, Canada—a complete trans-Atlantic crossing taking 82 days. Local residents may move only 100-500 km to deeper water, while long-distance migrants travel 3,000-4,000+ km to southern destinations. Migration distance appears individually variable and not necessarily repeated annually.
3. Why do basking sharks migrate?
Basking sharks migrate primarily to follow seasonal plankton availability—their exclusive food source. Spring/summer brings massive plankton blooms in temperate coastal waters (Scotland, Ireland, Canada), attracting sharks for 3-4 months of intensive feeding. As autumn/winter arrives, surface plankton crashes, forcing sharks to relocate to areas with year-round productivity (southern waters, deep-water habitats). Secondary drivers include water temperature preferences (though recent research shows wide thermal tolerance -0.6 to 29.9°C) and possibly reproductive behavior (mating in summer grounds, potential birthing in winter areas), though reproductive drivers remain unconfirmed.
4. When do basking sharks migrate?
Basking sharks follow seasonal migration timing: Spring migration (March-May) brings northward movement to temperate feeding grounds; Summer residence (June-August) involves 3-4 months in coastal waters; Autumn departure (September-November) sees southward or offshore migration with peak departures in October; Winter distribution (December-February) finds sharks in deep local waters or distant southern locations. Migration timing triggers include changing day length (photoperiod), water temperature shifts (departures often when temps drop below 10-12°C), and declining plankton abundance. Individual timing varies by 4-8 weeks, with some sharks departing feeding grounds as early as late August while others remain through November.
5. Do basking sharks return to the same places each year?
Scientists don’t yet know if individual basking sharks return to the same locations annually or alter migration patterns based on body condition, reproduction, and food availability. Satellite tags typically track sharks for 6-12 months (one migration cycle), with few multi-year tracking studies. However, population-level data shows strong site fidelity to summer feeding grounds—the same regions (Scotland, Ireland, Canada, California) consistently host concentrations May-August. Whether individual sharks return to identical spots or migrate differently each year remains an open research question. Some evidence suggests pregnant females may have different patterns, but confirmation requires longer tracking studies.
6. How deep do basking sharks dive during migration?
Basking sharks dive to extraordinary depths during migration, with typical deep dives reaching 200-800 meters (656-2,625 feet) and the record maximum at 1,264 meters (4,147 feet)—deeper than most military submarines operate. During winter migration, sharks may spend weeks to months at mesopelagic depths (400-1,000 meters) feeding on deep-water zooplankton without surfacing. Many exhibit diel vertical migration patterns, diving deeper during daytime (400-800m average) and shallower at night (200-400m), following vertically migrating plankton. Summer feeding occurs at shallow depths (0-30 feet), creating dramatic seasonal depth variation. Deep-diving capability allows access to tropical waters by utilizing cool, productive mesopelagic zones.
7. What tracking technology is used to study basking shark migration?
Scientists primarily use Pop-up Archival Transmitting tags (PSAT/PAT tags) attached to basking shark dorsal fins that record depth, temperature, and light levels for 6-12 months before detaching, floating to the surface, and transmitting data via satellite. Geolocation algorithms use light levels (sunrise/sunset timing, day length) and sea surface temperature to estimate location (±50-150 km accuracy). Some sharks receive SPOT (Smart Position or Temperature) tags that transmit real-time location when surfacing, though these provide limited winter data when sharks rarely surface. Recent 2025 advances include improved machine learning geolocation, behavioral state modeling, and integration with oceanographic models, increasing accuracy to ±25-50 km.
8. Do all basking sharks migrate the same way?
No, basking sharks exhibit remarkable behavioral plasticity with individuals adopting different migration strategies. Satellite tracking reveals three main patterns: (1) Local residents staying within 500 km of summer grounds, diving deep for winter; (2) Medium-distance migrants traveling 800-2,000 km to Bay of Biscay; (3) Long-distance migrants moving 2,000-4,000+ km to Portugal/North Africa or crossing oceans. Even within populations tagged at the same location and time, individuals show varied behaviors. Factors influencing strategy may include sex, age, reproductive status, body condition, and individual preference. This plasticity complicates conservation efforts requiring protection across multiple migration routes and destinations.
9. Where do basking sharks migrate in summer?
Basking sharks migrate to productive temperate coastal feeding grounds during summer (May-August), with major destinations including: Scotland (Inner Hebrides, Isle of Skye, West Coast), Ireland (West Cork, Kerry, Clare), Cornwall England, Isle of Man, Norway (including Arctic regions), Canada (Bay of Fundy, Nova Scotia, Newfoundland), New England USA, California (Monterey Bay), Iceland, New Zealand, South Africa, and Southern Australia. These locations share characteristics: cold-temperate waters (8-14°C/46-57°F), continental shelf habitat, massive spring/summer plankton blooms, nutrient upwelling, and productive frontal zones. Sharks show strong site fidelity, returning to same general regions annually for 3-4 months of intensive surface feeding.
10. How does climate change affect basking shark migration?
Climate change likely impacts basking shark migration patterns through multiple mechanisms, though long-term studies are lacking: Warming ocean temperatures may shift plankton bloom timing and distribution, potentially altering migration timing and routes. Earlier spring warming could advance northward migrations, while warmer autumns might delay departures from feeding grounds. Changing ocean currents (Gulf Stream, California Current) affect nutrient delivery and plankton productivity, possibly making traditional feeding grounds less productive. Ocean acidification impacts plankton communities (especially copepods with calcium structures), potentially reducing food availability. Expanding thermal ranges might allow sharks to utilize previously unsuitable regions. However, basking sharks show remarkable thermal tolerance (-0.6 to 29.9°C), suggesting adaptability. Long-term tracking studies (10+ years) are needed to document climate-driven changes.
Conclusion
Understanding basking shark migration has advanced dramatically over the past two decades through satellite tracking technology, revealing these gentle giants as accomplished long-distance migrants capable of traveling nearly 10,000 kilometers between seasonal habitats. Rather than following a single migration pattern, basking sharks exhibit remarkable behavioral plasticity—some staying local and diving deep for winter, others migrating thousands of kilometers south to warmer waters, and a few crossing entire ocean basins in epic trans-Atlantic journeys. These migrations are primarily driven by following seasonal plankton abundance, with individual sharks employing different strategies possibly based on sex, age, reproductive status, and body condition. As climate change continues altering ocean conditions and plankton distributions, ongoing tracking research remains essential for protecting these endangered filter feeders across their complex migration routes and ensuring conservation measures account for the full scope of their movements throughout the Atlantic Ocean and beyond.