Observing and Explaining Coastal Fishery Dynamics : An Application to Ports in California Cameron Speir, NMFS Caroline Pomeroy, California Sea Grant Jon G. Sutinen, University of Rhode Island Cynthia J. Thomson, NMFS
Research Question Given: Fishing industry changes over time Overall declining landings, revenue, participation Are all ports affected proportionally? How do inter-port dynamics compare to larger trends in fisheries and the industry? How do we explain what we see?
Study Area: Northern and Central 3 ports 34 fisheries 1981-27 fish tickets 27 1,178 vessels 25,343 fishing trips 137 million pounds $58.5 million California
1981-27 Trips and Revenue By Fishery Trips by Fishery - 1981 Revenue by Fishery - 1981 Other 18% Other 22% Groundfish-Trawl 23% Rockfish-Inshore 7% Groundfish-Trawl 8% Salmon 55% Crab 14% Crab 12% Albacore 19% Salmon 22% Trips by Fishery - 27 Revenue by Fishery - 27 Other 2% Crab 31% Rockfish-Inshore 4% Sablefish-Inshore 4% Other 1% Groundfish-Trawl 5% Coastal Pelagics 7% Crab 47% Sablefish-Inshore 7% Salmon 13% Rockfish-Inshore 16% Salmon 21% Groundfish-Trawl 15%
1981-27 Trips and Revenue By Port Trips by Port - 1981 Revenue by Port - 1981 17% Other 26% 17% Other 44% Fort Bragg 11% 14% 8% Monterey 9% Bodega Bay 11% Bodega Bay 7% Moss Landing 8% Monterey 8% San Francisco 1% Fort Bragg 1% Trips by Port - 27 Revenue by Port - 27 Other 24% 13% Bodega Bay 11% Princeton 7% Other 13% 2% Morro Bay 7% San Francisco 7% 9% Princeton 1% Moss Landing 9% Fort Bragg 1% San Francisco 9% Bodega Bay 9% Moss Landing 11% Fort Bragg 11% 2%
Trends in the commercial fishing industry 1 x 14 Coast-wide Fishing Trips and Active Boats: 1981-27 1 84,318 Fishing Trips Number of Trips 5 5,257 5 Number of Boats Boats 25,343 1,178 198 1985 199 1995 2 25 21
Trends in the commercial fishing industry 1.8 x 18 Coast Wide Revenue: 1981-27 1.6 1.4 $ 14 million (27 dollars) 1.2 Revenue- 27 $ 1.8.6 $ 59 million.4 81 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 Year
Research Question Given coast-wide decline in fishing activity: Are all ports affected proportionally? H : decline distributed proportionally across ports How do we measure differences? Rank correlation Differences in annual changes Regression analysis: test for constant vs. time trends Can we explain the differences, or lack of differences?
Rank Correlation Rank correlation Kendall s W Rank ports in order of revenue and trips in each year Compare rankings across years: how similar is the order from year-to-year?
Rank Correlation 1981 San Francisco Fort Bragg Monterey Moss Landing Bodega Bay Oakland Fields Landing Morro Bay 1991 San Francisco Bodega Bay Fort Bragg Princeton Morro Bay Monterey Point Arena Moss Landing 27 Fort Bragg Moss Landing Bodega Bay San Francisco Princeton Morro Bay Trinidad Santa Cruz
Differences in Annual Changes Calculate percent change at coast-wide and port levels Year-over-year Cumulative Test whether differences are significant A t-test for every port
Differences in Annual Changes (Year-over-year) No major ports differ significantly from the mean coast-wide percent change 8 Fort Bragg 8 +698 in 1986 Fields Landing +742 in 1993 6 6 +355 in 1994 +185 in 1995 4 4 +99 in 1992 2 2-2 -2-4 -4-6 -6-118 in 1987-112 in 23-8 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7-8 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 8 8 +217 in 26 6 6 +166 in 23 4 4 2 2-2 -2-4 -4-6 -6-8 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7-8 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7
Differences in Cumulative Changes Trips: 1981 Base Year (South of SF Bay) Avila Morro Bay 15 15 1 1 5 5-5 -5 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 Monterey Moss Landing 15 15 1 1 5 5-5 -5 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7
Differences in Cumulative Changes Trips 1981 Base Year (North Coast Ports) Fields Landing 15 15 1 1 5 5-5 -5 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 Trinidad 15 15 1 1 5 5-5 -5 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 82 83 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7
Differences in Cumulative Changes Revenue 1991 Base Year (North Coast Ports) Fields Landing 14 14 12 12 1 1 8 8 6 6 4 4 2 2-2 -2-4 -4-6 -6-8 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7-8 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7 35 Trinidad 14 3 NOTE SCALE 12 1 25 8 6 2 4 15 2 1-2 5-4 -6 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7-8 91 92 93 94 95 96 97 98 99 1 2 3 4 5 6 7
Differences in Cumulative Changes Ports differ from coast-wide changes Base year affects analysis Different time trends among ports
Differences in Cumulative Changes Ports Differ from Coast-Wide Changes Base year effects (1981 vs. 1991) 1981-27 1991-27 Ports with Positive Cumulative Differences Morro Bay Princeton San Francisco Bodega Bay Trinidad Moss Landing Princeton Trinidad Ports with Negative Cumulative Differences Monterey Fields Landing San Francisco Bodega Bay Fort Bragg
Analysis of Time Trends Four regression models dependent variable is port s share of revenue Null model constant only Time trend t = year index Time trend t 2 Time trend t 3 System of equations (SUR) Compare model fit (AIC, BIC)
Analysis of Time Trends Regression Results All trend combinations improve model fit Best fit: t + t 2 +t 3 (lowest AIC, BIC) Significant trends: Monterey, Moss Landing, Princeton, Bodega Bay
Do ports differ from coast-wide trends in fishing activity? Stable rankings No difference in changes year-over-year Cumulative changes exhibit some differences Some ports share of activity over time appears systematic
Implications Fishery participants are used to variability, but How does persistent decline affect ports? How much variability can ports deal with and maintain ability to adapt? What drives changes and differences regulations, fish stocks, economic geography?