Assessment of shark sighting rates by aerial ... - Fisheries Reports

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24 NSW DPI Table 5. Number of reported sightings by fixed-wing and helicopter crews during 10 days of joint coastal patrols. North-bound and south-bound flights have been pooled for each day. “Other” category comprises rays and unidentified objects. Date Aircraft Total shark Hammer head shark Unidentified shark Fish school Dolphin Other 22/12/2010 Fixed-wing 0 0 0 4 4 0 Helicopter 0 0 0 2 30 0 25/12/2010 Fixed-wing 8 5 3 14 39 1 Helicopter 1 1 0 19 67 1 28/12/2010 Fixed-wing 1 0 1 1 18 0 Helicopter 1 1 0 5 2 3 29/12/2010 Fixed-wing 0 0 0 6 0 6 Helicopter 2 2 0 15 22 3 01/01/2011 Fixed-wing 16 13 3 2 14 5 Helicopter 24 23 1 3 20 1 05/01/2011 Fixed-wing 0 0 0 8 45 0 Helicopter 5 5 0 9 65 3 08/01/2011 Fixed-wing 6 2 4 5 101 0 Helicopter 8 8 0 28 68 1 15/01/2011 Fixed-wing 0 0 0 2 63 0 Helicopter 0 0 0 2 106 0 22/01/2011 Fixed-wing 0 0 0 11 47 0 Helicopter 8 8 0 3 14 1 29/01/2011 Fixed-wing 0 0 0 1 15 0 Helicopter 4 2 2 9 43 5 Total 84 70 14 149 783 30 Larger groups of animals were sighted at the most frequent rate. Surface-oriented pods of dolphins were sighted most often, followed by fish schools (Fig. 10). Sightings of individual animals however, were extremely low. On average, a total of only 0.69 sharks were seen per 100 km flown by fixed-wing observers, and 1.18 sharks by helicopter observers covering the same area (Fig. 10). The fixed-wing observers did see three times as many unidentified sharks as the helicopter observers, although this was the lowest category of sightings. Robbins et al. Assessment of shark sighting rates by aerial beach patrols
NSW DPI 25 Number of sightings per 100 kms + SE 14 12 10 8 6 4 2 0 Total shark Hammerhead Unidentified Fish school Dolphin Other shark shark Sighting category Figure 10. Reported numbers of sightings per 100 kms during coastal patrols of NSW beaches. Open bars represent fixed-wing sightings, closed bars represent helicopter sightings. “Other” category comprises rays and unidentified objects. Only three of the 149 fish schools were identified as having sharks associated with them. Furthermore, on only 14 occasions were sharks recorded within two minutes flying time (~6.2 kms travelled for the fixed-wing aircraft and ~3.7 kms for the helicopter) of a fish school sighting (5 fixed-wing sightings, 9 helicopter). It is clear from these results that the presence of a fish school is not indicative of sharks present in the area. Assessment of shark sighting rates by aerial beach patrols Robbins et al.
Page 1 and 2: Assessment of shark sighting rates
Page 3 and 4: Contents i TABLE OF CONTENTS TABLE
Page 5 and 6: Acknowledgements iii ACKNOWLEDGEMEN
Page 7 and 8: NSW DPI 5 1. BACKGROUND 1.1. Aerial
Page 9 and 10: NSW DPI 7 2. METHODS 2.1. Study loc
Page 11 and 12: NSW DPI 9 The six flight transects
Page 13 and 14: NSW DPI 11 A B Figure 3. (A) Google
Page 15 and 16: NSW DPI 13 3. RESULTS 3.1. Depth ex
Page 17 and 18: NSW DPI 15 3.2. Distance experiment
Page 19 and 20: NSW DPI 17 Percentage of analogues
Page 21 and 22: NSW DPI 19 Number of analogues sigh
Page 23 and 24: NSW DPI 21 Table 3. Regression anal
Page 25: NSW DPI 23 3.4. Coastal aerial patr
Page 29 and 30: NSW DPI 27 too deep, or are in wate
Page 31 and 32: NSW DPI 29 4.3. Conclusion Severe l
Page 33 and 34: NSW DPI 31 Clark CW, Brown MW, Cork
Page 35 and 36: NSW DPI 33 Rowat D, Gore M, Meekan
Page 37 and 38: NSW DPI 35 No. 27 Rowling, K.R. and
Page 39 and 40: NSW DPI 37 No. 82 Silberschnieder,

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