Comparison of Cichlasoma minckleyi ram and suction feeding kinematics to those of other cichlid fishes

Authors: Hulsey, CD

Year: 2000 (xxxii)

Abstract

The feeding performance of biting morphs of Cichlasoma minckleyi on elusive prey was compared to the feeding performance of six other species of cichlids. Using high speed video (500 fps), we measured the contribution of both ram and suction to feeding strikes. Suction was quantified as the linear distance that the prey moved towards the predator once the predator began the fast opening portion of the gape cycle during the strike. We measured ram, the linear distance the predator travels towards the prey, in two ways. We quantified both the movement of the predator’s body towards the prey and body movement plus the additional contribution of upper jaw protrusion towards the prey. To quantify the strike variables of each cichlid species, we used three individuals ranging in size from 65 to 85 mm. We examined 15 brine shrimp, Artemia sp., and up to five guppy, Poecilia sp., capture events per individual. Surprisingly, the trophically diverse group of cichlid species examined did not differ from one another in the amount of suction produced when capturing either prey type (p < 0.65). Species did differ significantly in the amount of ram used during prey capture but only when feeding on the more elusive guppies (Body Ram: p < 0.056; Body + Jaw Ram: p < 0.047). Biting C. minckleyi displayed less body ram than the piscivores Cichla ocellaris , Crenicichla gayi , and Petenia splendida, but did not differ from Cyprichromis leptosoma or Astrotonotus ocellatus . The same pattern was found in the body + jaw ram

components of strikes except that C. minckleyi had significantly more body + jaw ram than Cyprichromis leptosoma. In general, we found that the distance traveled during the predatory strike of a cichlid fish is composed of several times more ram than suction, and that suction does not vary among predators or prey type. This analysis has important implications for the dichotomy of fish into ram versus suction feeding types and suggests that composite indices of feeding performance such as ram/suction ratios should be regarded with caution. Finally, it is predicted that if the piscivorous morphs of C. minckleyi were compared to biting morphs, the piscivorous morphs will not differ in the amount of suction produced but instead should use more ram during prey capture.

Resumen

Comparación de la cinemática de alimentación por embestida y de succión de Cichlasoma minkleyi con la de otros peces cíclidos Se comparó el desempeño alimenticio de morfotipos mordedores de Cichlasoma minkleyi sobre presas evasivas, contra el desempeño de seis otras especies de cíclidos. Mediante video de alta velocidad (500 pies/s) medimos la contribución de la embestida y la succión a los intentos de alimentación. La succión se midió como la distancia lineal que la presa recorrió hacia el depredador cuando el depredador inició la porción de apertura rápida del ciclo de mordisqueo durante el intento. Se midió la embestida, la distancia lineal que el depredador recorre hacia la presa, de dos maneras. Se midió tanto el movimiento del cuerpo del depredador hacia la presa y movimiento del cuerpo más la contribución adicional de la protusión de la mandíbula superior hacia la presa. Para cuantificar las variables de los intentos de cada especie de cíclido, se usaron tres ejemplares que variaron en tamaño de 65 a 85 mm. Para cada cíclido se analizaron los eventos de captura de 15 ejemplares de Artemia sp., y hasta cinco gupies, Poecilia sp. [probablemente P. reticulata]. De manera sorprendente, el grupo tróficamente diverso de peces cíclidos analizados no difirieron entre ellos en la cantidad de succión producida al capturar cualquiera de los tipos de presas (p<0.65). Las especies sí difirieron significativamente en la cantidad de embestidas durante la captura de presas aunque sólo cuando se alimentaban de los más evasivos gupies (embestida corporal: p<0.056; embestida cuerpo + mandíbula: p<0.047). El morfotipo mordedor de C. minckleyi mostró menos embestidas corporales que los piscívoros Cichla ocellaris, Crenicichla gayi, y Petenia splendida, aunque no difirió de Cyprichromis leptosoma o Astrotonotus ocellatus. Ese mismo patrón fue hallado en los componentes “embestida cuerpo + mandíbula” de los intentos, excepto que C. minckleyi mostró significativamente más “embestidas cuerpo + mandíbula” que Cyprichromis leptostoma. En general, se encontró que la distancia recorrida durante un intento de depredación de un pez cíclido se compone de varias veces más embestidas que succión, y que la succión no varía entre depredadores o tipo de presa. Este análisis tiene importantes implicaciones para la dicotomía de peces en los tipos de alimentación embestida vs. succión y sugiere que los índices compuestos de desempeño alimenticio tal como la relación embestida/succión debieran ser considerados con cautela. Por último, se predice que si se comparan los morfotipos piscívoros de C. minckleyi con los morfotipos mordedores, los piscívoros no mostrarán diferencia en la cantidad de succión producida, pero sí más embestidas durante la captura de presas.

MINUTES OF THE BUSINESS MEETING / MINUTAS DE LA REUNION DE NEGOCIOS President David L. Propst called the 32nd annual business meeting of the Desert Fishes Council to order at 1610 on 17 November 2000 in the auditorium of the National Park Service visitor center at Furnace Creek, Death Valley National Park, California. Following a request for old business, Dean Hendrickson requested an amendment to the minutes of the 31st annual business meeting at Ciudad Victoria, Tamaulipas, Mexico. Apparently Dean was cited in those minutes as stating that full articles would continue to be published in future would not publish full articles.” The error occurred in the transcription of meeting notes. This point is addressed again later in the meeting. Executive Secretary Pister then provided a financial statement for the Council. Balance in the DFC checking/savings account was $11,814.99 at the time of the meeting. In addition, the Council maintains approximately $4,601.94 in a separate membership account at the Arizona State University credit union, thus giving a grand total of $16,416.93. [Note: since the meeting a check in the amount of $4,000.00 was drawn to Death Valley Children’s Association to pay for the barbecue, and we will soon be billed approximately $3,000.00 for printing and mailing of Pro ceedings volume 31 (1999)]. Thus, given the above debits, the Council will have a balance of $9,416.93 which, when added to funds paid for registration and barbecue ($5,310.00), totals $14,726.93 to cover expenditures during 2001. Based on expenditures during previous years, this amount may allow us to add to the Council’s endowment fund, maintained as a Morgan Stanley Dean Witter Liquid Assets (money market) account, the interest from which is used to support student and foreign travel. The chair of the local committee for DFC 2000 (E. P. Pister) officially thanked the Bishop office of the California Department of Fish and Game for support and assistance in organizing DFC 2000. He also noted that Wayne Alley and his wife Lillian were instrumental in maintaining the registration table. There were 160 preregistered attendees, plus an additional 30 to 40 individuals that registered during the meeting. This amounts to approximately 200 attendees. Phil also noted that 33 colleges and universities were represented in the registration total, which may be the largest number ever recorded at the society’s annual meeting. Following the call for new societal business, President Propst noted that no resolutions were submitted this year for consideration by the society. The president then reminded all that resolutions are now submitted using the electronic abstract form located on the society’s webpage (http://www.desertfishes.org). Nathan Allan, the chair of the local committee for DFC 2001 then was asked to provide input on next year’s meeting. Nathan informed the society that DFC 2001 would be held in the new student center at Sul Ross State University (SRSU) in Alpine TX. SRSU has an enrollment of approximately 3,000 students, and the population of Alpine is circa 5,000. Alpine is at an elevation of 5,500 feet and is close to both the Davis Mountains and Big Bend National Park. The closest airports are at Midland and El Paso. The preliminary local committee is composed of the Nature Conservancy, the U.S. Fish and Wildlife Service, the Biology Department at SRSU, and the Chihuahuan Desert Institute. All are quite enthusiastic in that this is the first ever meeting of DFC in Texas and a TEXAS-style barbecue was promised. A regional symposium (“aquatic ecosystems of the trans- Pecos/Chihuahuan region) will be a part of the 2001 meeting. Dean Hendrickson then advised the society that DFC 2002 would likely be held in San Luis Potosi, Mexico. The society met in this city in 1984 and has been asked to return. Paul Barrett then extended an invitation for the society to meet in Tucson AZ for 2003. More information on both these upcoming meetings will be provided at DFC 2001. President Propst then noted that a vote of members would be required to resolve a difficulty with student papers submitted for the Hubbs and Miller awards. In the past, only the student presenter was allowed to be on the authorship line. However, Craig Stockwell requested that this be amended to allow additional individuals on the author line, but with the student presenting the paper. Thus, the question President Propst posed to the membership was: (a) student-only authorship, or (b) student plus two colleagues. Clark Hubbs initiated the discussion by suggesting that students only should be on the authorship line. Jimmy Johnson asked if it were permissible to have other students as well as the presenting student on the author line, rather than simply student and major professor. President Propst noted that this was covered under the proposed amendment. Steve Ross indicated that the southeastern division of the American Society of Ichthyologists and Herpetologists allowed additional authors on student submittals for awards. Marlis Douglas then argued that the research should be initiated solely by the student, and if indeed others are involved in organizing and/or completing the research, then the paper should not be submitted in the Hubbs or Miller award categories. Other discussants also

mentioned variations on these themes. President Propst called for a vote and the multiple author amendment won by approximately 20 votes. Nadine Kanim informed the membership that the DFC executive committee had recommended that abstract length for research and eco-region submittals be restricted to 500 and 1,000 words, respectively. Dean Hendrickson mentioned that this requirement was because Lloyd Findley and colleagues found it difficult and time-consuming to translate longer submittals. A plea was also made to properly edit abstracts prior to submittal. Often the translation committee had to reword abstract in English before the latter could be translated into Spanish. Dean further mentioned that the service Lloyd and his colleagues provided the society with regard to translation was completed under a modest stipend and their efforts were immensely important to the council. If DFC had to go to the open market for translations, it simply could not afford nor provide that service. Thus, length and proper editing of abstracts were important to ease the burden of the translation committee. At this point, President Propst reminded the membership that the Proceedings will no longer publish full articles. This was done for a variety of reasons, both financial and professional. Michael Douglas made the point that the Proceedings are gray literature, in that abstracts often represented work-in-progress, and articles are not adequately peer-reviewed. Grey literature is an immense problem in southwestern North America and the society need not contribute to its furtherance. The fact that the Proceedings has an ISSN number actually makes it appear as if the Proceedings is a true journal, but this is not so. Camm Swift agreed that it was inappropriate to publish full articles in the Proceedings because the latter is merely a synopsis of oral presentations at the meeting and was never designed to publish full research articles. Bob Edwards then stated that full articles were most often reviewed prior to being published in the Proceedings because he had participated in that chore in the past. Jonathan Baskin then asked if it were possible to have a straw vote on the issue of publishing full articles in the Proceedings, just to get a feel for societal intent. President Propst called for an unofficial vote on the subject of publishing full articles in the Proceedings. Only four individuals voted affirmatively for publishing of full articles. A second suggestion put forth by the executive committee for membership vote was the question of converting the Proceedings into an electronic publication. It was felt this would save the society over $2, 000 to 3,000.00 per year in publication costs. These monies could be earmarked for a variety of other uses. Those members who so wished could print the Proceedings themselves from the DFC webpage using their desktop printer. Jimmy Johnson questioned how long the 2000 Pro ceedings would be retained on the DFC web page. Dean Hendrickson responded that files for the past 7—8 years were already available and they would continue to accumulate. Paul Holden spoke in favor of having a printed and bound copy, in that it was immediately available and visible. Jonathan Baskin concurred. Erik Gustafson spoke in favor of the electronic version, as did Michael Douglas. President Propst called for the vote and it was recorded as: Yes (36), No (50). Thus, the Proceedings will remain as a printed and bound journal available to members. Dean Hendrickson pointed out that the society’s listserver (DFC-L) now had 337 subscribed members. All current members to June, 2000 have been automatically added to the listserver. The executive committee felt this was an ideal medium to communicate issues of importance to all members, and in turn have members send notices to the society at large. However, due to difficulties with alias names and additional e-mail addresses, it was decided that in the future all members must be responsible for maintaining their own subscription to DFC- L. The society will no longer assume this role. Michael Douglas then asked if a message could be sent via DFC- L to all members to verify subscription. If a member received no such message by 1 December, then it would be safe to assume said member is not linked to the DFC-L and must establish their own link if they so wish. Dean Hendrickson concurred that such a message would be sent. (After the meeting, on November 18, 2000, a message containing the following instructions was sent to DFC-L: To sign off from DFC-L, send an email to listproc@lists.cc.utexas.edu that contains only the following request: unsubscribe DFC-L To subscribe to DFC-L send the following request to the same address: Subscribe DFC-L emailaddress@yourserver.xxx firstname lastname) [replacing “emailaddress@yourserver.xxx” with your own email address and “firstname lastname” with your own names] Nadine Kanim, eco-region coordinator, offered a heartfelt thanks to those who submitted Area Reports. Twelve of 13 eco-regions were represented. The lone exception was the Baja Mexico region. Nadine also mentioned that splitting of eco-regions according to agency affiliation went against the original idea of eco-

regions derived according to hydrology. The latter will be adhered to in the future. Thus, northern and southern NV eco-regions will be combined, as will NM and Upper Rio Grande regions. Finally, the Northwestern and Baja Mexico regions will also be coalesced. In closing, President Propst stated that the society needed volunteers to assist in web-based activities, abstract reviewers, and as members of the student awards committee. Astrid Kodric-Brown, Craig Stockwell, and Matt Andersen all volunteered for the latter duty. Tony Robinson mentioned that the American Fisheries Society was meeting in Phoenix 19—23 August 2001 at the Crown Plaza Hotel. Doug Threloff then reiterated directions to the upcoming picnic. President Propst adjourned the business meeting at 1650.

DFC HYDROLOGIC BASIN AND AGENCY REPORT COORDINATORS The following persons coordinated agency and other input to reports presented at this annual meeting. Contact them or authors of those reports for further information.

Oregon (State of): Doug Young, U.S.F.W.S., 20300 Empire Avenue, Suite B-3, Bend, OR 97701, Phone: (541) 312-6421, FAX: (541) 383-7638, Email: doug_young@fws.gov California (State of): Rebecca G. Miller, Habitat Conservation Planning Branch, Department of Fish and Game, 1416 9th Street, Sacramento, CA 95814, Phone: (916) 322-9092, FAX: (916) 653-2588, Email: BMiller@dfg.ca.gov Northern Nevada (North of Tonopah, except for the White River Drainage): Stephanie Byers, U.S.F.W.S., Reno Fish and Wildlife Office, 1340 Financial Blvd., Suite 234, Reno, NV 89502-5093, Phone: (775) 861-6300, FAX: (775) 861-6301, Email: stephanie_byers@.fws.gov AND Anita Cook, Nevada Department of Wildlife, 1100 Valley Road, Reno, NV 89512, Phone: (775) 688-1532, FAX: (775) 688-1595, Email: acook@ndow.state.nv.us Southern Nevada (including Ash Meadows): Jerry Stein, Nevada Department of Wildlife, State Mailroom, Las Vegas, Nevada 89158, Phone: (702) 486-5182, FAX: (702) 486-5133, Email: SteinFish@aol.com Bonneville Basin (northern Utah and southern Idaho): Paul Holden, Bio/West Inc., 1063 West 1400 North, Logan, Utah 84321, Phone: (801) 752-4202, FAX: (801) 752-0507, Email: pholden@bio-west.com Upper Colorado River (upstream of Glen Canyon Dam on Powell Reservoir, including Green, Gunnison, Dolores, and San Juan Rivers): Timothy Modde, U.S.F.W.S., Colorado River Fish Project, 266 W. 100 N., Suite 2, Vernal UT 84078, Phone: (435) 789-0354, FAX: (435) 789-4805, Email: tim_modde@fws.gov Lower Colorado River (including Little Colorado, Virgin, Bill Williams, and Gila rivers): Jerry Stefferud, U.S.F.S, Tonto National Forest, 2324 E. McDowell Road, Phoenix, AZ 85006, Phone: (602) 225-5200 x229, FAX: (602) 225-5295, Email: jstefferud@fs.fed.us New Mexico (State of): Jim Brooks, U.S.F.W.S., New Mexico Fishery Resources Office, 2105 Osuna N.E. Albuquerque, New Mexico, 87113, Phone: (505) 346-2538, FAX: (505) 346-2537, E-mail: jim_brooks@fws.gov Upper Rio Grande: Sue Swift-Miller, Rio Grande National Forest, 1803 West Highway 160, Monte Vista, Colorado 81144, Phone (719) 852-6228, FAX (719) 852-6250. Email: sswiftmiller@fs.fed.us Texas (State of): Gary Garrett, Texas Parks and Wildlife Department, Heart of the Hills Research Station, HC 7, Box 62, Ingram, Texas 78025, Phone: (830) 866-3356, FAX: (830) 866-3549, Email: gpg@ktc.com Northwestern Mexico: Alejandro Varela-Romero, Universidad de Sonora, DICTUS - Departmento de Investigaciones Cientificas y Tecnologicas, A.P. 1819, Hermosillo, Sonora, Mexico, Phone: [011] (52) 62 12 19 95, FAX: [011] (52) 62 12 32 71, E-mail: avarela@guayacan.uson.mx Northeastern Mexico: Salvador Contreras-Balderas, A.P. 504, San Nicolas de los Garza, Nuevo Leon, Mexico 66450, Phone: [011] (52) (8) 376-22-31, Home: [011] (52) (8) 313-16-41, E-mail: scontrer@ccr.dsi.uanl.mx Baja California: Gorgonio Ruiz-Campos, Universidad Autonoma de Baja, California, Ensenada, Baja California, Mexico, PMB-064, P.O. Box 189003, Coronado, California 92178-9003, Phone/FAX: (617)44560, Email: gruiz@bahia.ens.uabc.mx